Shadow the Hedgehog is an anthropomorphic hedgehog/Black Arms hybrid who resembles Sonic the Hedgehog in many ways and serves as his arch-rival and occasional ally. Shadow was created as the "Ultimate Life Form" by Gerald Robotnik by using the DNA of Black Doom and is the final result of Project Shadow. His purpose was to provide ways to develop a cure for incurable deadly illnesses, more specifically for Gerald's granddaughter Maria Robotnik, who he had a great bond with. However, he was eventually captured following his creation and put into stasis by G.U.N. when he was deemed as a threat to humanity. Fifty years later, Shadow was released by Dr. Eggman in order to assist him in his plan to conquer the earth. Initially, Shadow worked with him but secretly sought to destroy the planet in order to avenge Maria, who had been killed by the military, but was persuaded to save it from Gerald's doomsday plans. In the process, Shadow lost his memories and as such, sought to uncover the truth of his past, during which he met Black Doom and the Black Arms; in the end, Shadow regained his memories, uncovered the truth, and thwarted Black Doom's agenda and saved the world. From there, he continued his mission to protect humanity for the sake of Maria. Shadow is sharp-witted, always on edge, and has a strong sense of purpose, always willing to accomplish his goals by any means, and always serious. Essentially a dark version of Sonic, Shadow can match him in both speed and skill, and can use Chaos Control with a Chaos Emerald to warp time and space. While preferring to work alone and not one of his closest friends, he has helped Sonic and his allies when needed.

Doctor Ivo Robotnik, better known by the alias Doctor Eggman. He is a human scientist who boasts a remarkable IQ of 300 and a passion for machines. Eggman dreams of conquering the world to establish a global empire to build his utopia, Eggmanland. For all his brilliance though, his plans are constantly foiled by his arch-nemesis, Sonic the Hedgehog, and his friends. Never discouraged by his defeats, Eggman is always able to come up with a seemingly endless supply of plots to make his ambitions a reality. His ambitions and schemes ever growing, his plans have varied from using Animals to power his robots, known as "Badniks", to making incredibly dangerous global threats that have involved building war machines, using doomsday devices to threaten entire nations, and relying on ancient mythological deities or eldritch abominations bent on destruction, all in the name of achieving his goals. At times, Eggman has even gone as far as to target the entire universe and hatched schemes to control spacetime itself. While all of these plans end in failure due to the continued efforts of Sonic and his friends, the mad doctor is somehow always able to slip away from certain death or imprisonment and escape at the last moment. Eggman's immature character and self-centered thoughts have led to evil deeds, making him the most dangerous threat to ever appear in the universe.

The Eggman Empire is a political unit that advocates a global government ruling all of earth (and possibly even the universe). Its capital is called Eggmanland, where the regime's influence is planned to be spread from. The country is a totalitarian dictatorship in which all of the power is concentrated into the hands of Dr. Eggman. The country also has a cult of personality towards the doctor's image, as evidenced by the various titles and statues honoring him found in many of the empire's territories. The Eggman Empire employs propaganda and pressure to legitimate governments to assert its sovereignty, and spreads false or misleading claims such as that Eggman is actually benevolent or that the inability to think is akin to "living the good life".

Sonic the Hedgehog, born June 23, is an anthropomorphic hedgehog born with the ability to run faster than the speed of sound, hence his name. As his species implies, Sonic can also roll up into a concussive ball, primarily to attack enemies. Becoming a carefree adventurer at an early age, he has spent most of his life traveling around the world and far beyond, usually with his best friend, Tails, by his side. He has used his abilities to defend his world and those far beyond from the forces of evil, especially his arch-nemesis, Dr. Eggman, and his empire. During his many adventures, Sonic has traveled from the ends of the world to the far reaches of space and time, facing countless trials that have tested him to the fullest, earning him many titles, allies, and the scorns of several foes. Well-known for his attitude and somewhat short temper, yet strong sense of justice, compassion, and love for freedom and adventure, Sonic's countless victories over the villains he has faced and his extraordinary set of abilities both have given him somewhat of a celebrity status, having many fans who yearn for his cool lifestyle. However, he does not care about his image at all, and prefers to live his life his own way.

Miles Prower, better known as Tails, is a young anthropomorphic fox cub born on West Side Island who, due to a genetic abnormality, was born with two distinct twin-tails, hence his nickname. Due to his abnormality, Tails was a victim of bullying during his youth. One day, however, he met Sonic the Hedgehog and was inspired to be like him after seeing him run like the wind. Tails soon after began following Sonic on his adventures and has since become his best friend and sidekick. He is able to use his twin-tails to fly by rotating them like helicopter rotors and is a mechanic genius and aerial pilot. A bright, energetic, and curious fox, Tails was initially timid and lacked courage. After meeting Sonic, however, he has become more confident, eventually growing into a more outgoing, brave, independent individual and a hero in his own right. Since encountering Sonic, Tails has looked up to him and stood by his side in order to help him whenever he can, having travelled around the world and far beyond alongside him, usually to stop the ambitions of the evil Dr. Eggman.

The world's largest governing body consisting mostly of humans. The United Federation has a republican government with a President who resides in the capital city of Central City in a building known as the White House. It also has at least one ministry: the Minister of Finance, in charge of the country's finances. In terms of foreign relations, the United Federation appears to enjoy warm relations with Japan, another sovereign state. The United Federation's armed forces are the Guardian Units of Nations, which also operates internationally and houses several powerful weapons and robots in order to combat threats such as the Eggman Empire and the Black Arms. The United Federation is a large coalition of countries, each of which are controlled by their presiding government which themself answer to the Federal government. The United Federation doesn't have any sovereignty over South Island, West Island or Angel Island; generally being confined to the main continental landmasses.

Amy Rose is an anthropomorphic hedgehog with a crush on Sonic the Hedgehog. Since meeting Sonic on Little Planet, Amy has declared herself his girlfriend and has attempted to win his heart by any means in many of their adventures. She wields the Piko Piko Hammer, which she uses with skills second to none and never leaves home without. Amy is a cheerful, though slightly erratic girl, with a positive attitude and nature and boundless energy. However, she has a fiery temper and her infatuation with Sonic makes her short-sighted and a bit obsessive about him, having followed him everywhere since meeting him. Nevertheless, she has a pure heart and will not let anything stop her.

Amy's signature large two-handed hammer. Despite its colorful and innocent appearance, the Piko Piko Hammer is a powerful melee weapon, capable of dealing incredible damage with seemingly little effort. As a testament of its might, it could leave a massive dent on the Mirage Express with a massive blow, and can likewise destroy robots and send foes flying with a single swing. Additionally, even powerful individuals like Sonic fear getting a beating from the Piko Piko Hammer. It is, nevertheless, graceful enough to be used for high-speed techniques. When swung, it tends to leave a trail of pink hearts. Mixed with Amy's abilities, the Piko Piko Hammer can be used for many applications besides combat. When swung around fast enough and with the right amount of force, the Piko Piko Hammer can function as a propeller for flight, launch powerful shockwaves that can stir up miniature tornados, or unleash massive releases of energy, and provide boosts for different acrobatic maneuvers. Upon impact with any object or person the hammer makes a "Piko" sound; the sound is louder depending on the force of the impact.

A resistance group formed to protect individuals against Dr. Eggman who seek to undo the damage he's done to the planet and offer relief to those effected. Headquartered in Sunset Heights on South Island, the group is largely made of members from what was formerly "The Resistance" following the defeat of Infinite and the conclusion of the Eggman War. The Restoration is currently led by Jewel the Beatle and formerly led by Amy Rose.

Green Hill, also known as Green Hill Zone, is a natural paradise located on South Island. Green Hill was the first location Sonic the Hedgehog passed through during his mission to free South Island from the tyranny of Dr. Eggman. Green Hill is a giant field blessed with greenery and beautiful blue lakes. Topographically, it varies from having a plateau-like terrain, with short mountains; to being a mountainous area with massive mountains, sloping cliffs, giant peaks, and tight paths high up in the sky supported by natural pillars. Either way, the location is filled with large waterfall vistas, palm trees, and tropical flora of various types. Perhaps most distinctively, the soil is checkered brown, and most of the local plant life appears to have unfamiliar geometric appearances to it. As shown during the Sky Base incident and the Time Eater incident, Green Hill also has a series of dark, brown caves underneath it, which have small lakes and ponds of water in them. There are artificial structures made of wood as well, such as bridges, fences, totem poles, and scaffolding-like buildings. Perhaps what makes Green Hill unique is its "crazy" terrain. Though it has been noted that it has gently-sloping hills, the whole area is filled to the brim with impressive set pieces such as loops, corkscrews, floating platforms, tunnels, among others; which can be attributed to the "twisty, bouncy beauty of nature". During the Eggman War, Green Hill had a different appearance. While still a picturesque landscape for the most part, the region was partially turned into a desert, with its flora and soil adopting a yellowish color while the waters in the lakes and waterfalls had dried and since have been restored to their former splendor.

Seven ancient emeralds and secret stones tied to the Master Emerald that possess unlimited power. Those who hold them can use them to cause miracles and other feats, such as warping space and time and powering machines. Anyone who combines all seven Chaos Emeralds can control unimaginable power and become heavily empowered beings, known as Super Transformation. Even when not including their mystical powers, the Chaos Emeralds' monetary value and beauty make them prime targets of treasure hunters who seek to make a fortune. The Chaos Emeralds have observed numerous joys and sorrows since ancient times, being the center of countless world-threatening conflicts and targeted by multiple factions on earth and beyond, who seek them for their near-limitless powers. In the hands of villains, they have been used for doomsday weapons and schemes for world domination, and in the hands of heroes, they have been used to save the world. Over time, the Emeralds have been gathered multiple times, though they tend to scatter themselves after each usage and reset the hunt for them.

Recognizable by their black and red skin, they were a violent and hive-minded race of extraterrestrial beings created and led by Black Doom who traversed space in the Black Comet. Fifty years after the creation of Shadow the Hedgehog, they invaded earth to conquer the planet but were opposed by Shadow and his allies. The Black Arms were now assumed to be endangered, with the sole exception of Shadow being the last member of their species as a hybrid, after he chose to go against his own kind and destroyed the Black Comet using the Eclipse Cannon, as was its original purpose. There were numerous breeds of Black Arms, most of which being similar to various earthly creatures, including humans, non-anthropomorphic birds, and massive worms. Overall, all of these breeds possessed common features, such as two completely yellow eyes, and their trademark jet black and crimson skin. During infancy, the Black Arms underwent a larval phase, during which they were known as Death Leeches, before maturing into soldiers.

Vanilla the Rabbit is an anthropomorphic rabbit and is the respected mother of Cream the Rabbit. Vanilla lives close to Night Carnival with her daughter, Cheese, Chocola her companion, and Gemerl, and runs a successful Chao Garden together with them. Vanilla is a skilled homemaker who has taught her daughter polite manners under her kind, but strict, discipline.

Rouge the Bat is an anthropomorphic bat and jewel thief who has worked as a part-time government spy for the President of the United Federation and in close association with the Guardian Units of Nations. A world-famous treasure hunter, Rouge has a weakness for jewels, like the Master Emerald and Chaos Emeralds, which she always obsesses about. As a spy, Rouge is trained in combat, stealth and infiltration, and possesses both super-level kicking power and flight. Rouge is in short, an enigma, as her motivations are always in question and often mercenary in nature. In truth, she is usually just out for herself. She is incredibly smart, sassy, and seductive, and knows how to get what she wants. Once she has a target in mind, she always goes for it, regardless of the costs. Beneath her ditsy exterior though, she is a calculating realist and her motives are always mercenary in nature. Regardless, she is loyal to her closest friends and has more than once helped Sonic the Hedgehog and his allies save the world.

Knuckles the Echidna is an anthropomorphic echidna and the current guardian of the Master Emerald, a powerful ancient gemstone which is kept on Angel Island. Guarding it is his solemn duty to protect from anyone seeking to abuse it, as well as the sole surviving descendant of the echidna race from the Knuckles Clan. Known for his powerful and wild nature, his dominant traits are his super strength and the two spike-like knuckles on each of his gloves, from which his name is derived from, and which he can dig and climb walls with. He can also trap the wind under his dreadlocks to glide through the air. Knuckles is also one of Sonic the Hedgehog's oldest friends and rivals. A loner by nature, Knuckles is independent, headstrong, and serious, yet gullible and short-tempered to a fault. He is entirely devoted to his duty, spending most of his time on Angel Island protecting the Master Emerald, and rarely cares about anything that is of no importance. When his friends and others are in need of his help, however, Knuckles can always be relied on, being willing to leave his home very often.

The metropolitan capital city of the United Federation. The White House is located within Central City, as is the main tower HQ from which G.U.N. operates. Sonic escaped Central City some several years prior when G.U.N. had pursued him, having "mistaken" the hero for the then-recently-released Shadow. Locations within Central City include Mission Street and Westopolis.

Eggman's AI creation-turned-daughter; empathetic and seeking to have a family born of love. Helped Sonic stop a world-threatening ancient entity called "The End" during the Starfall Isles Incident. Considers Dr. Eggman and his creations to to be her family. Sage is allied to Eggman and the Eggman Empire.

The sinister leader of the Black Arms and the creator of his kind. For thousands of years, Doom planned to impose terror on the Earth and use the local human population as a livestock for his minions. Ultimately, however, he met his defeat at the hands of Shadow the Hedgehog, his own offspring. Black Doom has a jet black legless body with three red bestial eyes, twin wide horns with red tips, a set of spines on his scalp, three-fingered paws with claws, and no lips. For attire, Doom wears a dark brown worn robe with black-brown shoulder pads and golden accents, a maroon drape scarf with tattoo markings hanging from the back, golden chains with a set of silver-spiked medallions possessing a gem, and a double black cord necklace with red, blue and purple ornaments on one and golden and silver pendants on the other that resemble the Black Arms logo.

A city consisting mostly of Islanders (Non-humans) on South Island's Western coast.

Tails' home and workshop. Located within Emerald Town.

Angel Island, also known simply as the Floating Island. It is a landmass of miracles and mysteries that floats high in the sky using the eternal energy of the Master Emerald; without it, the island will inevitably plummet from the sky. The island is inhabited by various Animals and is also the home of Knuckles the Echidna, who is the guardian of the Master Emerald and the only surviving member of the Knuckles Clan that once inhabited the place.

Soleanna is a city in the middle of a lake. It has many bridges and boats. It is near a desert and a jungle.

A massive aircraft carrier created by Dr. Eggman that served on a few occasions as his base of operations during his attempts to conquer the earth circa The Chaos Incident. The Egg Carrier had been crewed by the doctor and his various robots, including the first E-100 Series robots. The original version fell into the ocean after a mighty battle, but other iterations of the battleship were made over time to take its place and subsequently destroyed.

Station Square is a heavily populated city famous for its many attractions including an amusement park, a hotel/restaurant, and a casino district. A train station in the city allows travel to the Mystic Ruins. It has a human population of 2,856,427 and a near-resemblance to New York City and Boston. The city was heavily damaged by massive flooding as a result of the god of destruction, Perfect Chaos, during the Chaos Incident; Perfect Chaos was subsequently defeated by Super Sonic. The city has mostly recovered, though the impact left in Chaos' wake is still felt by the city's denizens.

Metal Sonic is an evil, ultra-high performance, very advanced Badnik version of Sonic the Hedgehog that was created as a secret weapon by Dr. Eggman for the sole purpose of destroying the blue hedgehog. Modeled with extreme accuracy after Sonic, Metal Sonic not only resembles his organic doppelgänger, but can also imitate his moves and achieve speeds matching and even exceeding the hedgehog's own. The brainchild of Eggman, he is by far his greatest creation and one of his "magnum opuses". First deployed during the Little Planet incident, Metal Sonic confronted Sonic in battle and lost, though he would repeatedly return to challenge Sonic and his allies as Eggman's "too-sharp sword". While usually serving as Eggman's obedient and silent enforcer, Metal Sonic is an intelligent robot with a very dark side. A cold-hearted, aggressive, and ruthless killer, he is obsessed with proving his superiority to Sonic and eliminating him for good to the point where he has rebelled against Eggman more than once to achieve his goal. However, he always fails in the end, only to later return more powerful than before. To this day, Metal Sonic remains one of Sonic's most dangerous foes.

Tangle the Lemur is an anthropomorphic ring-tailed lemur from Spiral Hill Village and a member of the current generation of Diamond Cutters. She first became acquainted with Sonic the Hedgehog and his friends during the fallout after the Eggman War, having sprung into action to defend her village from one of the Badnik hordes terrorizing settlements across the earth. Since then, she has been a recurring participant in the adventures of Sonic and his allies.

Whisper the Wolf is a heroic anthropomorphic wolf and a current member of the second generation of Diamond Cutters, a rapid-response Restoration team. She is aided by her own personal team of Wisps. Known for using a Sniper Wispon in combat and her overall soft-spoken nature. Only really trusts Tangle. After her previous unit, (the first generation of Diamond Cutters,) was murdered by it's traitorous infiltrator Mimic, Whisper swore to avenge her friends.

A colossal battle station built by Dr. Eggman once in the past with the intent of forcing the United Federation to surrender, built in the facsimile of his own face. Destroyed by Sonic and Tails, it then crashed into Angel Island; it was lifted into the atmosphere where it was then destroyed again by Sonic, Tails and Knuckles.

The backbone of the Eggman Empire, Egg-Pawns are badniks that serve as their creator's main force of weapon robots in his army. Specially given their costs, the Egg Pawns have been described as excellent robots. Although each of them is weak, the Egg Pawns' immense numbers and versatility make them perhaps the greatest threat in Eggman's army. They also come in different varieties, each one having its own unique skillset. Egg Pawns are humanoid robots primarily orange in color, with a round body and a dome-shaped head that come together in an egg-like shape. It also has blank cyan eyes, a sharp yellow nose, a wide glowing panel for a mouth, and a black lower torso section. More recent models have received additional armor, like thicker forearms and armored legs, but less articulated shoulders.

Mass-produced, ladybug-based Badnik model created by Dr. Eggman. Typically used as scouting units, Motobugs have round red body armor with vents covering their backs and blue faces which come together with their bodies in an almost spherical shape. Their source of locomotion is reliant on the simple wheel mechanism located in their undercarriages. A small engine with an exhaust pipe on both sides of their rear propels their wheels across the ground. They also have short arms with yellow forearms and a single claw at the tip.

A detective agency consisting of Vector the Crocodile, Espio the Chameleon and Charmy Bee. Operates out of Central City. Former members include Knuckles the Echidna, Ray the Flying Squirrel and Mighty the Armadillo.

Vector the Crocodile is an anthropomorphic crocodile and the current director and head honcho of the Chaotix Detective Agency, which he founded with his close friends Espio and Charmy. Large and imposing with a kind heart beneath his scaly exterior, Vector is ready to take any job that pays, but will always help those in need for free, a charitable nature leaving his agency perpetually short on money. Known for his great love of music, Vector's trademark is a pair of headphones which he always listens to. Despite his rough appearance and sometimes rude manners indicating otherwise, Vector is a capable detective and natural leader with a clear, deductive mind who will always see cases through until he deems them solved. Friendly, albeit loudmouthed.

Lanolin the Sheep is an anthropomorphic sheep from Riverside and a member of the Restoration. She is responsible for the creation of the second generation of Diamond Cutters.

The increasingly uncommon flesh-and-blood foot soldier of the villainous Eggman Empire. Not frequently seen on the battlefield, they have a cunning and strategic wit their robotic counterparts direly lack in owing to their organic nature; this has served to their detriment at times, being prone to reasoning, fear and compassion that might come at odds with their orders. This force consists of both humans and non-humans, being a consistent mix of the two. It's due to the human nature within these soldiers that Eggman largely favors using a robotic workforce; flesh is fallible and robots feel no fear, working tirelessly to fulfill his orders without need for sleep, food or deviation from design - Exactly as they're programmed.

Surge the Tenrec is an anthropomorphic tenrec with villainous and modified cyborg enhancements implanted by Dr. Starline and with no memories of her past, and the companion of Kitsunami the Fennec. She was made for the sole intended purpose of destroying Sonic the Hedgehog and replacing him as the hero of the world. However, after discovering the secret of her origin, Surge would begin seeking revenge on everyone she blames for her past life being taken away from her. Capable of Electrokinesis, Super speed, Enhanced agility & Enhanced durability. Hates Eggman, Starline and the Restoration.

Kit is an anthropomorphic fennec fox who was modified into a villainous cyborg by Dr. Starline with no memories of his past. He was designed for the intended purpose of supporting Surge the Tenrec and replacing Miles "Tails" Prower. After discovering their origins, Kit would assist Surge in her plan to get revenge on those responsible for their old lives being taken away from them.

A fabled race of cruel demon-like warriors native to the satellite planet Lost Hex that is led by their strongest warrior and prince, Zavok. For a scheme, Dr. Eggman enslaved a group of Zeti known as the Deadly Six, only for them to rise up against him due to an accident caused by Sonic the Hedgehog. However, the Zeti were defeated by Sonic before they could achieve their goal of destroying the world. The Zeti are humanoid in terms of overall physical appearance but possess some unique key features. Common physical characteristics Zeti share are hands with five digits that each have a claw-like nail, two-toed feet with a claw-like appendage on their heels and animalistic tails. Each Zeti also possesses a number of striped horns on their head, with the number of the horns differing between each individual, though two appears to be the most common. The average height for a Zeti is about 118 centimeters (~3'10"). The skin color of the Zeti comes in vastly different varieties, which has been seen so far to be red, neon pink, orange-yellow, sky blue, lime green and white. They also possess equally distinct hair colors, which can range from between cyan, purple and bright green, though it can turn white from aging. Common color characteristics Zeti share are the remainder of their skin from the waist down being black and their eyes having yellow sclera. The individual Zeti can have their own unique physical proportions and features; Zavok is muscular and bulky with a fairly standard humanoid shape, Zazz is very lanky and thin, and Master Zik's head and body come together in an indistinguishable spherical shape. Additionally, the Zeti's tails and horns can come in different sizes and shapes as well, and Zeti like Zavok and Zazz can have spikes on their bodies. Almost nothing of Zeti culture is known. In fact, the only Zeti culture implied is the apparent custom of naming with the first letter "Z," as every member of the Deadly Six has a name beginning with said letter.

A mysterious, unexplored continent floating in the sky above the world, and houses a variety of different areas. Lost Hex is also home to the Zeti, a race of creatures that include the Deadly Six. The Lost Hex is made up of many hexagonal plates. Each of them is a piece of land or sea. They are either connected to each other or separated by large gaps. Together, they form somewhat of an incomplete sphere. The Lost Hex also has no nucleus, as the continent has only an empty space in its center. However, despite what its appearance might imply, it is not an independent planet, but rather one of the satellites that orbit the world. The Lost Hex's surface consists of numerous ecosystems. The continent features grassy meadows and hills, deserts, dense forests, snowy mountains, tropical coasts, and valleys filled with lava and volcanoes. However, characteristic that all these locations share are simple shapes that dot the landscapes, such as squares and rectangular cubes. There are also floating landmasses all over the Lost Hex in the shape of spheres or tubes in all kinds of shapes and sizes.

The Starfall Islands are an archipelago of several islands that house a myriad of set pieces across their unique biomes, including dense forests, expansive grass fields, towering mountains, overflowing waterfalls, sizzling deserts, coastal beaches, and ancient monuments and gardens. Not quite entirely devoid of urbanization, the Starfall Islands are home to a number of ancient ruins from a past, yet highly advanced civilization that used to exist on them. In addition, strange robotic enemies roam the various islands. The islands are inhabited by the species known as Koco, lead by the Elder Koco. The archipelago is also subject to a meteor-shower phenomenon known as the Starfall.

"Islander" or "Gaian" is a blanket term often used to refer to the anthropomorphic non-humans that inhabit the non-continental landmasses, regardless of their specific species.

Gemerl is a robot created by Dr. Eggman from Emerl's data, making him an upgraded version of his predecessor. Gemerl once aided the doctor in his attempts to stop Sonic and his friends from foiling one of his plans but wound up betraying his creator to cause mayhem. After his defeat, he was reprogrammed in the image of his predecessor.

Eggmanland, alternatively spelled as Eggman Land, and previously called Robotnikland, is a city/theme park hybrid that is considered by the infamous Dr. Eggman to be his ultimate robotic utopia. Eggmanland is the proposed capital of the Eggman Empire, from which the doctor seeks to spread his rule over the world. Though Eggman continues to strive towards building Eggmanland, his plans are usually foiled by Sonic the Hedgehog and his allies, and when he does manage to build it, it usually gets torn down or abandoned when his grander plans go awry.

An island that is known to be a treasure trove of gems and ancient ruins, that supposedly shifts along the water due to some connection to the Chaos Emeralds. Green Hill Zone is located here.

Holoska is a giant ice-covered continent which is inspired by the Inuit villages of the Arctic, along with the landscape and wildlife of the Antarctic due to the penguins and giant whales found there. It also has similar features to Greenland, the Arctic and Antarctica.

Apotos is a quaint port town located in Greece, at the tip of the European peninsula. It is based on the Cycladic-styled architecture of Greek cities, and its windmills are derived from the Greek island of Mykonos. It also has a strong resemblance to the Greek city of Santorini. This port town is well known for its ocean-side view, beautiful architecture, friendly people, as well as its Chocolate Chipped Cream Sundae Supreme.

Maria Robotnik was a young human, the granddaughter of Gerald Robotnik and the cousin of Dr. Eggman. Born on Earth, Maria suffered from a terminal illness with no known cure. To save Maria, Gerald brought her aboard the Space Colony ARK to keep her condition in remission, while he worked on Project Shadow in hopes of developing a cure. Gerald's research produced Shadow the Hedgehog, with whom Maria became close friends. When G.U.N. later shut down the ARK, Maria was killed by a G.U.N. Soldier while trying to assist Shadow in his escape from the colony. Her passing had a major impact on Shadow's psyche, and proved to be an event that would strongly influence the fate of the world in the decades that followed.

Professor Gerald Robotnik was a human scientist and the grandfather of Maria Robotnik and Dr. Ivo "Eggman" Robotnik. Prof. Gerald was a world-renowned scientist who is widely acknowledged as one of the greatest scientific minds of all time, responsible for several groundbreaking creations such a the Chaos Drive, including his greatest achievement, Shadow the Hedgehog, making him a modern day scientific Da Vinci. Over fifty years ago, Prof. Gerald was asked by the President of the United Federation to lead Project Shadow, a medical program for inventing immortality, which he accepted in hopes of finding a cure for a fatal illness afflicting his granddaughter Maria. Eventually, Gerald managed to create Shadow the Hedgehog, though not without drastic measures; he was taken into custody by the military when his work was deemed too dangerous - In actuality a ploy to capture and weaponize Shadow. When learning that Maria had been killed by the military, Gerald slipped into madness and spent his last days in captivity plotting revenge against humanity and being forced to finish work on Shadow up until Gerald's execution.

Gaia is a deity often attributed with the creation of the planet with worship primarily focusing on druidic practices and preservation of the world. Gaia worship is scarce, even following the Dark Gaia incident; Gaia is believed by many to have been the creator of the non-human races. Gaia is neither light nor dark Gaia, but rather the complete entity composed of both halves prior to its split before recorded history. Worship is often characterized by the recognition of both the light and dark elements of the deity, not viewing them as being split incarnations but rather two sides of the same coin, necessary to maintain balance in nature and life.

Light Gaia, AKA Chip is a primordial entity from the dawn of time and the incarnation of light, day and rebirth. Since the earth's beginning, Chip has been in an eternal conflict with Dark Gaia to protect the planet, where they maintain a cycle of destruction and rebirth of the world. In the present day, Chip was awoken prematurely by Dr. Eggman when he tried to harness Dark Gaia, losing his memories as a result. He later met Sonic the Hedgehog and the two of them worked together to recover Chip's memories and bring the planet back together after Dark Gaia shattered it. After restoring his cycle with Dark Gaia, Chip returned to dormancy.

Dark Gaia is a primordial hyper energy organism from the dawn of time and the incarnation of darkness, night, and destruction. Since his birth, Dark Gaia has been in an eternal conflict with Light Gaia over earth, where they maintain a cycle of destruction and rebirth of the planet. In the present day, Dark Gaia was awoken prematurely by Dr. Eggman, who planned to use his power to establish Eggmanland, which caused Dark Gaia to break apart and scatter across the world. After being reassembled, Dark Gaia attempted to destroy the world, but was defeated and returned to dormancy by Sonic the Hedgehog and Light Gaia, restoring his cycle. Dark Gaia is a gargantuan creature of such size that he makes characters like Sonic seem like grains of sand by comparison. In his incomplete base form, he has brown skin with his lower body and torso resembling that of a snake's, two thin arms with long neon-blue claws, and scaly shoulders. His head is very wide, much wider than his main body and is mostly composed of his jagged mouth (which remains closed until he transforms) and has a single green eye on each end of it. His central face looks like that of a reptile's, with four small horns on the top of his head, white eyes, and one large green eye on the middle of his forehead. On his back, Dark Gaia has seven purple flaming energy tentacles sticking out from him, and neon blue scaly fins that run from his lower back up to his head. He also possesses "hair" in the form of purple energy that emits from his head and back, giving it the appearance of a mohawk. Dark Gaia seems to change size throughout the course of his debut. When he first awakened, he was large enough to put one hand on either side of the earth, but during the final fight, he was noticeably smaller and fit inside the earth with plenty of extra space in the planet's core. This is probably due to Dark Gaia's mass being spread out and incomplete, as SA-55 (Orbot) states later on. The counterpart of Light Gaia, Dark Gaia originates from the beginning of time, having been spawned in the core of the earth after the planet first came into being. While their origins are unclear, Professor Pickle has speculated that both Dark and Light Gaia are manifestations of the planet's desire for a balance between light and darkness.[6] As per his purpose, Dark Gaia sought to destroy the planet that spawned him. In opposition to that, Light Gaia sought to protect the planet from Dark Gaia. Thus began an endless conflict between the two entities, forming a continuous cycle of destruction and rebirth of the earth over the eons. In this cycle, Dark Gaia would incubate in the earth's core for millions of years, gathering negative energy from the world to mature while sleeping. He would then awaken during the time of awakening as Perfect Dark Gaia and break the planet apart before trying to destroy it. Each time, however, Dark Gaia would be defeated by Light Gaia, who would rebuild the world and return Dark Gaia to dormancy, thus restarting the cycle. If Dark Gaia succeeds his mission, all life on the planet will perish, and the dead planet will enter a deep slumber until Light Gaia's arrival.

He is an immortal mutant Chao and a godlike figure who serves as the guardian who was worshipped by the Knuckles Clan prior to their negative turn of events, as well as the Chao and their friends. His body is composed entirely of concentrated energy, and he has the ability to change form and evolve with each Chaos Emerald that he absorbs. The first known guardian of the Chaos Emeralds, Chaos watched over a Chao colony in ancient times. However, 3,000 years ago, an attack from the Knuckles Clan led to him being consumed by a fury that threatened to destroy the world, but he was sealed in the Master Emerald before he could succeed. In recent times, he was released by Dr. Eggman for a plot to conquer the world. Despite initial cooperation though, he eventually revolted and tried to destroy the world. Fortunately, he was soon calmed by Sonic and departed in peace.

Solaris is the sun god of Soleanna, as well as a super-dimensional lifeform and a god of time, who is worshiped by the people of Soleanna. Originally a living flame, Solaris was split into two halves during the Solaris Project: Mephiles the Dark (his conscious mind) and Iblis (his raw power). Both of Solaris' halves were subsequently sealed away. Ten years later, Mephiles and Iblis were freed and rejoined, recreating Solaris who sought to destroy time itself, but was defeated by Super Sonic, Super Shadow and Super Silver. Solaris was subsequently erased from existence, ensuring his wrath would never be unleashed on the world.

Team Dark is consistent of Rouge the Bat, Shadow the Hedgehog and E-123 OMEGA. Despite typically being associated with G.U.N., Team Dark is in fact mercenary in nature, Rouge often serving as the main point of contact for missions and payment.

The home dimension of Blaze the Cat and many others, as well as a parallel dimension in the multiverse. Several artifacts of immense power reside here, such as the Sol Emeralds and the Jeweled Scepter.

The palace Blaze the Cat rules the Sol Empire from. The Imperial Palace bears large white structures with mainly purple, flat, conical and hemisphere-shaped roofs. Some buildings of the palace hold up large gray spheres. Some of the buildings bear golden, spear-like structures on the top of them. Other roofs are designed to be gray and are hemisphere-shaped or frustum-shaped.

One of the major tourist attractions in Station Square, Twinkle Park is a gargantuan theme park with a Disneyland-like feel. The scenery looks like outer space, while the park itself is set near the massive Twinkle Park Castle, a stone castle with red roofs. Other major attractions include the "Twinkle Coaster" and "Mirror House". The former is said to be very popular, and the latter is a series of dark, tight corridors with mirrors instead of walls; these mirrors are unique in that certain parts of the floor, which will lead to a pit when stood on, are not reflected in them. Aside from that, Twinkle Park has some occasional vegetation and a few water pools. Due to its popularity, there were once rumors about seven glowing stones being hidden in Twinkle Park, with the couple that managed to find them being able to make their wishes come true. Due to the blazing speed of the Twinkle Coaster, finding them was a very difficult tasks, with most couples giving up even after trying countless times

The Phantom Ruby is a magenta icosahedron ruby with black ripple patterns along its surface. It is also small enough to fit in the palm of a hand. The ruby can take control of people's visual and depth perception to feed false information to the brain, creating a new reality for them. Like a dream so real, if you bump yourself in it, your sleeping self will bruise. The ruby was presumably destroyed when Eggman was defeated at the end of the Eggman War, as it hasn't been seen since.

Blaze the Cat is an anthropomorphic cat from earth in the Sol Dimension, where she is both the imperial princess of the Sol Empire who has the right to inherit the throne, and the appointed guardian of the Sol Emeralds, a role similar to that of Sonic and Knuckles combined and that of a shrine maiden, although she appears too busy for such an admirable position as the latter. Despite being in a position of considerable power, Blaze tends to escape her castle and act rather freely and independently. As her name suggests, she is gifted with the power of pyrokinesis, which lets her create and manipulate fire in any way she pleases. Possibly due to her sheer strength, Blaze often acts without her royal guards to protect her. Blaze is normally calm and elegant but tends to conceal her true feelings. Devoted to her position, she sometimes gets herself bogged down by her own strict discipline, which made her anti-social, shy, and unfamiliar with the concept of having friends. After spending time with Amy and Cream and meeting Sonic however, Blaze has discovered the true meaning of friendship, allowing her to accomplish tasks for the good of her people and the innocent which she could never do alone. Despite the initial boundaries separating them, Blaze now travels freely between her dimension and Sonic's to visit her friends.

Mass-produced, bee-based Badnik model created by Dr. Eggman. The classic Buzz Bomber resembles a mechanical mud dauber with a black coloring around its spherical thorax. The stinger at the tip of its blue-striped abdomen is a rail detonator cannon, its primary weapon. Two mechanical devices resembling pale wings give it the ability to hover. Also, two engines are installed into the sides of this Badnik's thorax. Finally, the classic Buzz Bomber has a blue head with cartoony eyes, two mandibles and yellow antennae.

Mass-produced Badnik based on their creator, Dr. Eggman. In addition to being powerful soldiers on the battlefield, the Eggrobos are smart-bots designed to carry out tasks in the scientist's stead, making them a crown jewel in his attack force. The Eggrobos are fully egg-shaped humanoid Badniks, based on Dr. Eggman's appearance before the Chaos incident. As such, their middle torso is red with yellow downward-pointing triangles on the front while their lower torso is black with two silver buttons on the front. Their gray head area is clean with two small red eyes and a flat jaw fastened by yellow bolts. On their back they have two yellow and gray rockets for flight. They also have thin robotic arms and legs with round shoulders, white gloves and black shoes with white straps.

Mass-produced, crab-based Badnik created by Dr. Eggman. Crabmeats are slow-paced Badniks that are capable of shooting projectile balls or homing missiles from their pincers. Crabmeats, as their name implies, are inspired by real life crabs. The original Crabmeat models had red cephalothoraxes with gray underbellies and four gray and short crustacean-based legs with claw-like feet, which allowed them to scuttle around. They also had gray eyestalks protruding from an oblong hole in their cephalothoraxes with two cartoonish photo receptors located on top of each of them, and two short antennae above their eye stalks. They also had two cable-like gray arms with large and round pincers on the end of each arm. Hidden inside their pincers are also devices that let them fire either laser spheres or missiles (depending on their model).

mass-produced, caterpillar-based Badnik model created by Dr. Eggman that possesses a hard defense system and the ability to scatter its segments if destroyed incorrectly. Based on caterpillars, the Caterkillers' body consists of four spherical segments with curved yellow spikes on the sides. They also have two antennae located at the tip of their heads. They are mainly purple in color, with white fangs in their mouths, gray underbellies, and two antennae with yellow tops. They also have cartoonish, black eyes.

mass-produced, piranha-based Badnik model created by Dr. Eggman. Choppers are not very menacing, but they can launch surprise attacks from below bridges and water routes. Based on piranhas, the Choppers universally have a red mechanical body with a white dorsal fin, pectoral fins, anal fin and fishtail. Their pectoral fins in particular are attached to blue bases. They also have serrated teeth which they flash at all times. Their size has also varied over time, being either around the size of Sonic or much larger.

Mass-produced, monkey-based Badnik model created by Dr. Eggman, which throws explosive coconut bombs at their target from palm trees. The Coconuts model is a monkey-based Badnik that has a somewhat sphere-shaped red body. Their heads are red and their ears are round tin plates. They also have cartoony black eyes and small black noses. In addition, the Coconuts' faces and half of their bellies are colored peach. Coconuts also have gray and red arms, feet and a metallic monkey tail each that is a part of their gray-colored lower bodies.

Mass-produced, mantis-based Badnik created by Dr. Eggman that can toss its sharp claws at foes. Possessing a green, sliver and white color scheme, a Slicer's head is flat with two black eyes with yellow sclera and two metallic mandibles. Each of their two hands has a razor-sharp claw attached to it, which are their primary weapons. Slicers also have thin legs, and each foot's heel has small wheels, which they use to move around with slowly.

Mass-produced, chicken-based Badnik model created by Dr. Eggman. Basically a fixed battery, its function is shooting bullets at intruders. Being based on chickens, the Cluckers have white upper bodies, while their lower bodies are hidden inside their turrets. They also have red wattle/tail feathers, eyes with a strict stare, a small yellow beak each, two antennas connected to the sides of their heads by grey bases, and two small wings for steering their turrets. The turrets themselves have a small grey cannon on the front. The lower section of their turrets however, are a part of the environment, meaning they do not disappear upon a Clucker's destruction.

Mass-produced, starfish-based Badnik model created by Dr. Eggman. Asterons are simply designed and are located usually on walls and are able to self-destruct and fire its five sharp parts in many directions. The typical Asteron has a simple, flat starfish-shaped appearance. Its core body is colored light-yellow and in the middle of its body is a gray hole with a red eye in the hole. All five points on the Asterons also have gray spears on their tips.

mass-produced, crab-based Badnik created by Dr. Eggman. Usually found in casino-themed Zones, the Crawls are armed with bumper shields and pincers. The typical Crawls have rotund, gray torsos with a vent on their bellies and a neckless red or orange head with insectoid mandibles and two cartoonish black eyes. Possessing short limbs, they each also have a yellow crab-like pincer on one arm while the other wields a Bumper with a red background, blue center and a yellow/white star in it.

One of Eggman's aide robots, Orbot mainly assists the doctor in his schemes for world domination and makes sure his plans are carried out correctly, with his partner Cubot working alongside him to perform various duties. Internally Orbot's designation is Sentient Aide Model #55. Serious and intelligent, Orbot is loyal to Eggman. However, he does not like him very much, and his spiteful sarcasm sometimes provokes the anger of his creator. Orbot is a diminutive robot with a round head composed of a semi-spherical cap with a smaller black semi-sphere under it for a lower face. His lower face can separate to reveal a cover, representing his mouth, and he has two gray-framed and pupil-less eyes. He has also a ball joint for a chest and red gloves for hands. His arms and back consist each of two thin bars that are joined by a ball joint. His lower body is a small semi-sphere with a gray inside and a ball joint connecting it to his back. Orbot has a red head cap and light blue eyes and mouth, while the rest of him is black and gray with a few red joints.

a robot built by Dr. Eggman. One of Eggman's aide robots, Cubot mainly assists the doctor in his schemes for world domination, with his partner Orbot working alongside him to perform various duties. While loyal to Eggman, Cubot is dim-witted and lazy. He also has a faulty voice chip which causes him to randomly switch between different accents and personalities. Cubot is a diminutive robot, but slightly taller than Orbot. He has a black square head with a flattened, yet wider yellow square cap on top and a larger black square on the bottom, the latter of which resembles a jaw. His jaw can separate from his head to reveal a light blue cover resembling a mouth. He also has two gray-framed and pupil-less light blue eyes. His chest consists of a smaller yellow cube, and he has yellow gloves for hands. His arms and back consist each of two thin gray bars that are joined by a black and yellow ball joint. His lower body is a black open cube with a gray inside and a ball joint connecting it to his back.

Silver is an anthropomorphic hedgehog who comes from two hundred years into the future, where his purpose is to prevent the ruining of his time by resolving the catastrophes of the past, resulting in frequent interactions with Sonic and the rest of his friends and allies. For his mission, Silver makes use of his telekinetic abilities, which in his time are considered the norm, which allows him to manipulate the environment with the power of his mind. Silver is a kind-hearted and well-meaning individual, driven by a strong sense of justice to right the wrongs of the past in order to uphold peace, though he can sometimes be naïve and immature. Despite the monumental tasks he may have on hand, he is an optimist and will do whatever is required to protect the world.

Commander Abraham Tower is a human military leader and member of Guardian Units of Nations' high command, as well as one of the most respected. During his childhood when his family was aboard the Space Colony ARK, he befriended Maria Robotnik and witnessed the creation of Shadow the Hedgehog. After the ARK was invaded by G.U.N., the Commander blamed Shadow for his family's death. He carried a grudge against the hedgehog for fifty years, until he discovered the truth about him and Gerald Robotnik, the latter of which he had considered insane.

G.U.N. - an abbreviation of Guardian Units of Nations, is an international military and security organization on Earth, as well as the national defense forces of the United Federation. Run by a shadowy advisory council, G.U.N. has engaged in multiple incidents where it would protect earth from all sorts of threats, including the threats posed by the Eggman Empire and the Black Arms invasion. Founded over fifty years ago, G.U.N. has had a key role in several crises in recent history, including the shutdown of Project Shadow, the Space Colony ARK incident, the Black Arms' invasion of the planet, and many others. However, during the Eggman War, G.U.N. was "put in their place" by the Eggman Empire, forcing the organization into a less directly militarized function and instead into a extra-governmental counter-terrorism and intelligence agency tasked with maintaining both national and global security. Their primary goal is, as of the moment at least, to combat the ongoing threat of the Eggman Empire following the Doctor's return.

A global war that occurred in the recent history of earth between the Eggman Empire and Earth's governing bodies. The war lasted for a total of six months. Easily one of the largest, if not the largest, conflicts in recorded history, the war was fought over the control of the world after Doctor Eggman launched a campaign for world domination using the recently acquired Phantom Ruby. After defeating Sonic the Hedgehog with the assistance of the mercenary Infinite, the Eggman Empire began effectively spreading its influence across the globe. To liberate the world from the Eggman Empire's tyranny, the friends and allies of Sonic formed the Resistance and their own army. The ensuing conflict between the Resistance and the Eggman Armada marked what became known as the 'Eggman War'. However, the Resistance could do little during the early stages of the war, and the Eggman Empire eventually took over more than 99% of the planet within months. It was first during the last days of the war when the recently liberated Sonic, along with new allies, joined the fight that the Resistance began pushing the Eggman Empire back, eventually winning the war altogether. In the aftermath of the conflict the Resistance was reorganized into the Restoration, a group whose goals were to offer aid to those impacted by the devastating campaign.

In the "Angel Island incident", it turned out that the Death Egg had actually not been destroyed; following the previous events, it began falling into the earth's atmosphere and collided with a floating landmass known as Angel Island. This crash of catastrophic proportions caused the island to fall into the surface of the ocean, resulting in massive tsunamis around the world. Having survived this calamity, Eggman detected energy fields of the Master Emerald. Wanting to use this powerful gem to relaunch his space station, the scientist began kidnapping Animals for his Badniks yet again. Eventually, he came across Knuckles the Echidna, the guardian of this massive Emerald, and falsely claimed that he was a kind scientist who was researching the Death Egg's crash and that Sonic was coming for the Master Emerald. Falling for Eggman's lies, Knuckles promised to help him drive Sonic off the island upon his arrival. Days after the Death Egg's crash, Tails caught a strong Chaos Emerald signal on his Emerald Detector. Following this lead the two arrived at the island using the Tornado, however, Knuckles ambushed Sonic, causing the hedgehog to lose the Chaos Emeralds, which the echidna picked up and ran off with. Soon after, the heroes began making their way through the floating island's various regions, recollecting the Emeralds along the way. Despite facing countless setbacks, they eventually made it to the Launch Base, where the Death Egg was undergoing the last few repairs, and got onboard the station just as it began taking off. There, they faced Eggman's most powerful mechs. Despite the odds, the doctor was again defeated, and the Death Egg - due to the battle having taken place during a critical point of its launch - crashed back onto Angel Island's volcano, Lava Reef, while Sonic and Tails landed on Mushroom Hill. Knowing that the Death Egg would soon be relaunched yet again, Sonic and Tails continued their adventure across Angel Island while resisting various setbacks from Knuckles and Eggman. After boarding Eggman's Flying Battery, Sonic and Tails landed at Sandopolis, where they made their way to the Lava Reef. At the heart of this area, the doctor activated the Death Egg's laser eyes, causing the volcano to become active. After managing to escape from this place, the duo entered the Hidden Palace, where they had a confrontation with Knuckles. However, their encounter was interrupted when they saw Eggman steal the Master Emerald despite the echidna's best attempts to prevent this. Without the Emerald where it belonged, Angel Island began falling down. Realizing that he had been tricked, Knuckles guided Sonic and Tails to the celestial Sky Sanctuary, where they had several battles against the scientist's Mecha Sonic Mk. II before barely boarding the Master Emerald-powered Death Egg which was leaving the atmosphere. After overcoming the hazardous badniks and traps the duo faced Eggman's Giant Eggman Robo, powered by the Master Emerald itself. When this massive mech was destroyed, the doctor tried to escape one last time with the massive Emerald in his Egg Mobile, as the Death Egg itself finally crumbled and got completely destroyed, but his attempts ended in vain. Afterwards, Sonic transformed into Sonic Sonic and gave chase to the mad scientist, who was using his Final Weapon in a last-ditch effort to escape with the massive gem. The hedgehog pursued and defeated Eggman, retrieved the Master Emerald and, along with Tails, returned it back to Angel Island, which began ascending into the sky again. After this showdown, the Death Egg saga came to a close.

Following his victory on Little Planet, Sonic boarded his biplane, the Tornado, and left off in search for adventure, eventually finding and stopping at West Side Island to rest, unaware that Eggman was following him. Soon after landing on the island, the doctor kidnapped the local Animals for his Badniks to find the seven Chaos Emeralds that were said to be resting there according to legend. The villain's plan was to use the gems as a power source for his newest orbital weapon/space station: the Death Egg. Meanwhile, Sonic met Miles "Tails" Prower, a young fox with two tails and a great passion for machines, and the two quickly became best friends. A few days later, when Eggman began to terrorize West Side Island's regions to find the Chaos Emeralds, Sonic and Tails set out to stop him. While making their way through the island's various areas, the duo collected the seven Emeralds and had numerous encounters with the doctor. With the gemstones in his hands, Sonic was also able to attain a Super transformation - Super Sonic - for the first time. Eventually, the heroes boarded the Tornado to chase after the scientist in his Wing Fortress battleship. However, an ensuing assault caused the biplane to be heavily damaged and begin to fall off, thus forcing Sonic to continue on his own. After bringing the warship down, the hedgehog saw Eggman escape in a space rocket to outer space. Fortunately, Tails returned with a repaired Tornado and helped Sonic grab ahold of the doctor's rocket. Soon after, the hedgehog found himself boarding the Death Egg, which had been finished and launched with no Chaos Emeralds. Following a showdown between Sonic and Eggman, who was piloting his Death Egg Robot mech, a chain-reaction caused the Death Egg to begin exploding, forcing the hedgehog to go back to the earth as Super Sonic, where he reunited with Tails as the space station was seemingly destroyed.

In what became known as the Little Planet incident, following the South Island incident in his campaign to take over the world, Dr. Eggman learned of the appearance of Little Planet - a mystical planetoid that appears over the earth's Never Lake region once every year - and the seven Time Stones that were resting there that were said to be capable of controlling time itself. Coveting these stones to conquer the world, he trapped the planetoid inside of a nasty metallic shield that was chained to one of the mountains in Never Lake. Eggman then sent his Badniks to Little Planet to wreak havoc. These events caused the future of the planet to be a desolate wasteland ruined with pollution and machinery. Upon learning of his nemesis' actions, Sonic traveled to Little Planet, where he learned that he could undo Eggman's operations by going back to the past and destroying a "robot transporter" there. A while after his arrival, he met Amy Rose - a female hedgehog deeply in love with him - who got kidnapped by Metal Sonic, a deadly robot created by the doctor to counter Sonic's abilities. Making his way through Little Planet's regions, Sonic liberated them from his adversary's control, resulting in "good futures" with harmony and peace. Upon arriving at the Stardust Speedway city, the hedgehog encountered Eggman and Metal Sonic, the latter of whom challenged him into a deadly race. When he won, Sonic rescued Amy and then freed Little Planet from the scientist's control when he destroyed the doctor's Metallic Madness base.

The known beginning of Eggman's campaign to take over the planet: The South Island incident is when Eggman (Then still known only as "Robotnik") learned of the six Chaos Emeralds resting on South Island and carried out a massive invasion in the hopes of collecting the fabled gems. The doctor kidnapped all of the local Animals to use as power sources for his army of "Badniks" and built his fortress, the Scrap Brain, as a base of operations. Sonic, who lived on South Island at the time, rose against Robotnik's machinations; pursuing the doctor across the island before finally arriving to the Scrap Brain base, Chaos Emeralds in-hand, defeating Robotnik. With Robotnik's first defeat Sonic unknowingly set in motion a rivalry that would endure for several years, bringing peace back to the island and his home. Releasing the gems, they filled the decimated locale with flora before being seen flying off to West Side Island along with a seventh Emerald.

Extreme Gear are capable of allowing their rider to fly, or at least hover, at high speeds. Depending on the model, they are powered by Air, Gravity Points, or Ring Energy. These types of fuel are used for using speed boosts to accelerate the rider to high speeds, in a technique known as Kick Dash. In addition, Extreme Gear powered by Air can drop miniature Tornadoes to trip up rivals. Certain models of Extreme Gear each come with a variety of unique abilities, such as the ability to grind on rails, glide through the air, smash barricades and obstacles in the rider's path, or improve their own attributes. Some come with components of such abilities called Gear Parts, with which the user can alter the capabilities of their Gear. Most Extreme Gear even have their own abilities equipped in them, such as the Gambler's ability to manipulate the number of Rings the player earns in a race based on the position they come in. It is still unknown the maximum speed Extreme Gear can reach, or whether this maximum speed is shared to all Gear or is only exclusive to certain models. However, it was once stated that Sonic himself can use Gear to go even faster than when running on foot; as the hedgehog can reach supersonic speeds (915-3,840 mph), this would hint that at least certain models of Extreme Gear can reach speeds that exceed 3,840 mph.

Clutch the Opossum is an elderly criminal ringleader, he eventually retired and became an expert Chao trainer and the reigning champion of the White Park Chao Racing Circuit. After his mistreatment of his Chao was revealed, however, Clutch was forced to flee White Park Zone. Having lost much of his wealth following this incident, he is currently working on rebuilding his criminal empire with the aid of Rough and Tumble.

Cream is an anthropomorphic rabbit who is the daughter of Vanilla the Rabbit. She is also a friend of the Chao, especially to her dear Chao friend Cheese, who she takes with her everywhere. Originally living an idyllic life with her family, Cream had a chance encounter with Sonic the Hedgehog and his friends when the evil Dr. Eggman entered her world, and soon began joining them on their adventures. She is able to achieve flight by flapping her large ears. Cream is very polite, well-mannered and pure, though she can be childish, shy, and naïve. She is full of curiosity and tries her best in everything she does. Though young, she is not afraid to stand up for herself and will always be there to help out her friends. Just as Tails is the sidekick of Sonic, Cream serves the same purpose for Amy Rose and Blaze the Cat.

Marine is an anthropomorphic raccoon and a sailor from Southern Island in the Sol Dimension. When she began her travels, Marine met Sonic the Hedgehog, Tails and Blaze the Cat and joined them on their seafaring search for the Jeweled Scepter, during which she formed everlasting friendships. Always energetic, Marine is talkative, but rarely listens. A spunky yet lovable rascal, she is a lover of excitement and constantly seeks adventures. She aspires to become the captain of her own ship so she can travel the world, but can be quite the handful. During her adventures with Sonic though, she has matured and has promised to grow up more.

Big the Cat is a large, purple, anthropomorphic cat who lives deep within Mystic Ruins. Though imposing of stature, Big is gentle, calm and easy-going, though somewhat dim-witted person with a heart of gold. He also possesses incredible strength and toughness that makes him one of Sonic's strongest allies. He is also an expert fisherman. Big spends most of his time fishing in tranquility with his best friend, Froggy. Not one for going on grand adventures, Big prefers his peaceful and quiet lifestyle in the jungle. However, should his friends be in danger or in need of his aid, Big will not hesitate to leave his home to help them out and protect them in any way he can such as when he joined up with Team Rose.

Dr. Eggman discovered the Starfall Islands and their connection with the Ancients. Coveting this society's technology for his own use, the doctor set up labs across Kronos Island and began developing his operations, which included creating an AI codenamed "Sage" to help in his vile plan. Meanwhile, Tails was doing research on the Chaos Emeralds when he tracked the fabled stones to the Starfall Islands, noticing that they were mysteriously gathering. After he and Sonic helped Amy destroy a horde of Badniks on a nearby island, they traveled to Kronos Island in the Tornado. When they were approaching the landmass, however, an atmospheric charge caused the fox to lose control of the plane, and he and the two hedgehogs were sucked up by a wormhole that sent them to Cyber Space. Fearing that Sonic might foil his plot, Eggman installed Sage into a drive and traveled through the Starfall Islands, where he put his drive into one of the Portals to activate it. However, since he began being attacked by Ancient robots, Sage incidentally caused him to enter Cyber Space, where he found himself trapped with his AI and his Egg Mobile to survive. In the interim, Sonic miraculously escaped this hostile dimension and landed on Kronos Island, where he began a new adventure.