Gates are magical portals that connect the human world to the Dungeons. Gates are usually blue in color and can spawn just about anywhere, from inside a high school to the middle of a highway to the middle of an abandoned neighborhood. They remain open until the Dungeons they are led to are cleared. Much like how it is with Hunters and Magic Beasts, the threat level of a gate is categorized by the standard E-S class rank system. As a result, E-Rank gates are considered very low-risk, while S-Rank gates put entire countries in a state of emergency.

Dungeons are pockets of the chaotic world that are connected to the human world through gates. They generally contain a horde of monsters, which are led by a boss, and remain open until the boss is killed. Once the boss is killed, the dungeon will stay open for about an hour before closing on its own.

Essence Stones are small glowing stones that are found inside the corpses of Magic Beasts. They are generally very valuable and serve as the primary source of income for most Hunters around the world alongside Mana Crystals. Naturally, an Essence Stone's worth is determined by its rank and quality. The color of an Essence Stone depends on its rank. D-Rank Essence Stones are white, A-Rank Essence Stones are red, and S-Rank Essence Stones are purple.

Magic Beasts, also called the Denizens of Chaos, are magical monsters that reside inside Dungeons. Due to the manipulations of the Rulers, the vast majority of them are extremely hostile towards humans. Much like the Hunters who fight them, their power levels vary from individual to individual and thus their threat levels are categorized by the same E-S class rank system.

Mana is a form of natural energy previously foreign to the human world, integrated into it after the appearance of the Gates. At the same time, certain people 'Awakened' with the integration of Mana into their bodies, acquiring various magical abilities. Mana is the source of most skills and magic, marking the strength of a Hunter. Once it permeates the body, Mana usually makes it strong enough that anything without Mana can't cut or pierce through it.

Hunters are humans who are 'Awakened' and fight magic beasts and clear dungeons. As hunters turned out to be the only ones who could kill magic beasts and close gates, a global billion-dollar industry eventually developed around them as a result. They are also usually organized inside guilds. Hunters are ranked by class ranks, with E-Rank being the weakest and S-Rank being the strongest. There are also two general categories of hunters, combat and non-combat, and six different specific types of hunters: Fighters, Mages, Assassins, Tankers, Rangers, and Healers.

Mana Crystals are a blue-colored, magical mineral found inside Dungeons. Although they aren't worth as much as Essence Stones due to not containing as much Mana, they can still sell at high prices and serve as a secondary source of income for Hunters around the world. As machines that run on electricity don't work inside Dungeons, Hunters are required to mine mana crystals by hand. As a result, Guilds typically have entire teams of hunters dedicated to just mining crystals.

The Rulers are an ancient race of angelic humanoids and the arch-enemies of the Monarchs. The Rulers are spiritual creatures and lack organic form, meaning that they cannot descend into the human world without suitable human vessels. Unlike the Monarchs, the Rulers borrow their vessels for their bodies and allow them to retain full control.

The Monarchs are an unknown ancient race of monsters who seek to wipe out the human race. As a result, with the exception of Ashborn, they serve as the primary antagonists of humanity. Monarchs are comparable to National Level Hunters in power, if not even stronger. Monarchs lack shadows, and follow the orders of Antares, the Monarch of Destruction.

National Level Hunters are hunters who rival a nation's entire military in strength. These hunters are beyond S-Rank due to how much more powerful they are compared to the average S-Rank Hunter and possess extraordinary capabilities unique to themselves. Each National Level Hunter has also cleared at least one S-Rank gate entirely on their own. Only five National Level Hunters exist. It is unknown that National Level Hunters have been granted power by the Rulers.

Double Awakening, also known as Reawakening, is when a hunter undergoes a second awakening and receives a significant boost in strength, bypassing their previous natural limits. The results can be pretty drastic, to the point that there have been E-Ranks who have risen up to C-Rank and B-Ranks who have risen up to S-Rank.

A Red Gate is a special gate that completely seals off its entrance once humans pass through it. Aside from its red color, a Red Gate differs from a normal gate in that it seals off its entrance once someone walks through it, trapping the humans already inside the gate and preventing anyone else from the outside from entering the gate. After this happens, the gate will not open until one of three things happen: the boss is defeated, the entire raid party is killed, or a dungeon break occurs. The minimum difficulty level of a Red Gate is also at least B-Rank, meaning that the hunters inside the gate are doomed if there isn't at least one A-Rank among them.

The Cartenon Temple, also known as the Double Dungeon, was a mysterious hidden Dungeon that appeared within two separate D-Rank dungeons. It also served as the base of operations for the Architect and was used by Ashborn to find a human who was worthy of serving him as his host and inheriting his powers as the Shadow Monarch.

Rune Stones are runic items that drop from magic beasts. What makes rune stones special is that they contain unique skills, typically from the monster that dropped the stone. As a result, they are very valuable to hunters.

Eternal Slumber is a supernatural sleeping disorder that first appeared when humanity was exposed to the existence of Magic Beasts. Those who come down with this disease are intolerant to mana and as a result, they typically begin to develop symptoms after being exposed to a human who radiates mana, namely a hunter, for an extended time. Initially, the victim will begin to pass out against their will for much longer than normal, before fully succumbing to the disease's effects and falling into a coma.

False Rankers are hunters who are able to control the amount of mana that they output, allowing them to conceal their true abilities and rank a lot lower than they should. The big problem with false rankers is that most of them are heartless psychopaths who kill other Hunters for fun. Fortunately, they are said to be very rare.

Guilds are organized groups of hunters that raid gates. The leader of a guild is called the Guild Master and for top guilds around the world, Guild Masters are typically S-Rank Hunters. Top guilds tend to actively recruit high-level hunters with large bonuses depending on rank. As a result, joining a top guild ensures access to large salaries and a higher degree of safety, since raids are carefully and meticulously well-planned.

Ashborn was the King of the Dead and the Monarch of Shadows. He was also the strongest Ruler and the Greatest Fragment of Brilliant Light. Ashborn was a huge, muscular shadow warrior with glowing flame-like purple hair, glowing purple eyes, two curved black horns, and sharp claws.

The Jeju Island S-Rank Gate was a S-Rank Gate that spawned in Jeju, Korea. The gate spawned on Jeju Island about four years ago. Due to how weak the Korean S-Rank Hunters were at the time, they failed to close the gate and it eventually underwent a dungeon break, resulting in the deaths of thousands of Korean civilians and turning the island into a wasteland no longer fit for human habitation.

China is the largest country in East Asia. It is a military superpower, with more S-Rank Hunters than any other nation in Asia, and is one of the four countries that have managed to clear at least one S-Rank Gate without any outside help. Unlike the rest of the world, China ranks their hunters using a 1-5 star system instead of the standard E-S ranking system.

USA, otherwise referred to as America or the States, is a country located in North America. It is a military superpower, with more S-Rank Hunters than any other nation in the world, and is one of the four countries that have managed to clear at least one S-Rank Gate without any outside help. It is also the homeland of two of the five National Level Hunters.

Japan is an island country located in East Asia. Japan has 21 S-Rank Hunters.

Korea is a country on the Korean peninsula. Although Korea originally had ten S-Rank Hunters, only six are still alive; The other four were all killed in action. Korea is also known for having some of the weakest S-Rank Hunters in the world and for being the only country to have ever lost a portion of its land (Jeju Island) to an S-Rank Gate. As a result, the country had a poor international image of its hunters.

The Korean Hunters Association is a governmental organization in Korea that oversees the hunters, gates, and guilds within the country. Its headquarters is located in the Guro district of Seoul.

E-Rank Hunters are hunters who are stronger than normal humans and can use mana. E-rank hunters are the weakest of the hunters.

D-Rank Hunters are far stronger than E-Rank Hunters, and have access to more skills.

C-Rank Hunters are far stronger than D-Rank Hunters, and gain access to more powerful skills.

B-Rank Hunters are much stronger than C-Rank, D-Rank, and E-Rank hunters. B-Rank Hunters gain slight fame.

A-Rank Hunters are far stronger than B-Rank Hunters, and have access to more influence compared to the lower ranks.

S-Rank Hunters are extremely rare and are beyond the strength of A-Rank Hunters. S-Rank Hunters are famous, with common civilians knowing their names on the spot. S-Ranks vary in strength, due to the large difference in power between each individual S-Rank Hunter.

Ruler's Authority, also called Capture, is a telekinetic skill exclusive to the Rulers and their human vessels. Ruler's Authority is a form of telekinesis unique to the Rulers and the humans who have been granted their powers. Given how strong the Rulers are, at full strength, this skill is almost like a black hole in potency. It also does not cost any mana to use and can be applied over a large radius

Japanese Hunters Association is a governmental organization in Japan that oversees the hunters, gates, and guilds within the country.

Korean Hunters Auction is a market for hunters in Korea to purchase or sell equipment or materials obtained from raids.

The Federal Bureau of Hunters is a governmental organization in America that oversees the Hunters, guilds, and Gates within the country.

The Hunters Guild is the strongest and largest guild among the top five Korean guilds. It is active in the Seoul Metropolitan Area and is the only guild in Korea to have two S-Rank Hunters. Due to being the largest guild in Korea, the guild has two strike squads instead of just one. The first squad is led by Choi Jong-In and Cha Hae-In, and aside from them, consists of entirely A-Rank Hunters. The second squad is led by Son Kihoon and consists of both A-Rank and B-Rank Hunters.

Choi Jong-In, known as 'The Ultimate Soldier', is a Korean S-Rank Mage Hunter who specializes in fire magic and the Guild Master of the Hunters Guild. Choi is a lanky young man with red hair in a curtain hairstyle that is parted over the left side of his right eye.

Cha Hae-In, rarely known as 'The Dancer', is a Korean S-Rank Fighter Hunter and the Vice-Guild Master of the Hunters Guild. Cha is an attractive young woman with gray eyes and blonde hair in a bob cut. Cha is one of the strongest S-Rank Hunters in Korea.

Son Kihoon is a Korean A-Rank Tanker Hunter and the leader of the Hunters Guild's second strike squad. Kihoon is an athletic young man with spiky black hair and a friendly face.

Thomas Andre, known as 'The Goliath', is the strongest hunter in America and one of the five National Level Hunters, ranking 1st in the world. Thomas is a huge and muscular man with long blonde hair, red eyes, a toothy smile, an overgrown blonde goatee, and black tattoos. Thomas Andre is a Tanker Class.

Liu Zhigang is the strongest hunter in China and one of the five National Level Hunters, ranking 2nd in the world. Zhigang was a muscular and handsome young man with dark yellow eyes and long black hair that he wore in a ponytail, with several large additional strands of hair dangling from his head like leaves from a tree. Liu Zhigang is a Fighter Class.

Christopher Reed was the strongest hunter in America before Thomas Andre came, and is one of the five National Level Hunters, ranking 3rd in the world. Chris was a muscular young man with wavy brown hair that was shaved on both sides of his head, blue eyes, and slight facial hair.

Siddharth Bachchan is the strongest hunter in India and one of the five National Level Hunters, ranking 4th in the world.

Go Gunhee, known as 'S-Rank Among S-Ranks', was a Korean S-Rank Hunter and the Chairman of the Korean Hunters Association. Gunhee was a muscular old man with gray hair, greenish-gray eyes, and numerous scars on his body. Go Gunhee is very close to the power of a National Level Hunter.

Class Ranks refer to the international E-S ranking system for individuals who possess magical abilities and radiate mana from their bodies. It is primarily used to determine how strong they are and has been in existence for about 8-9 years. A hunter's rank essentially determines everything about them, including their income and their reputation as hunters. The disparities between ranks are also not easily overcome even after years of training and the gap in power between ranks can be very wide, as B-Ranks easily overpower C-Ranks and S-Ranks are exponentially more powerful compared to A-Ranks.

Awakening, also known as being 'Awakened', is a process that involves individuals gaining magical powers, and only those who undergo this awakening go on to become hunters. Normally, a hunter's rank is set in stone from the moment they awaken and the only way for their rank to increase is if they receive a second awakening, which is said to be very rare. The powers that they acquire enable them to fight dangerous creatures, known as magic beasts, that reside on the other side of the gates and are immune to conventional weapons.

Antares was the King of Dragons and the Monarch of Destruction. He was also both the strongest and the oldest of the nine Monarchs. Antares was a handsome and muscular middle-aged man with long red hair, a red beard, and glowing red eyes.

Baran was the King of Demons and the Monarch of White Flames. Baran was a huge, muscular demon with gray skin, glowing white eyes, glowing flame-like white hair, a long tail, and four horns on his head, two of which were very long and curved.

Rakan was the King of Beasts and the Monarch of Fangs. Rakan was a huge and muscular man with tan skin, glowing yellow eyes, sharp teeth, and wild black hair.

Sillad was the King of Snow Folk and the Monarch of Frost. Sillad was a muscular old elf with blue skin, long silver hair with a single long strand dangling over the right side of his face, blank white eyes, and round ears.

Legia was the King of Giants and the Monarch of the Beginning. Legia was a huge and muscular man with bluish-gray skin, long messy black hair with a sloppy beard, and glowing red eyes.

Querehsha was the Queen of Insects and the Monarch of Plagues. Querehsha was a tall, attractive, and very youthful-looking woman with glowing red eyes, pale skin, long flowing black hair, dark purple lips, large breasts, a voluptuous figure, and insectile characteristics, particularly on her legs and arms.

Yogumunt was the King of Demonic Spectres and the Monarch of Transfiguration. Yogumunt was an old man with gray hair, light red eyes, and a blood-red blob symbol on his torso. He wore a tattered blackish-purple hooded cloak, a pale yellow bone-like mask over his mouth, and two metallic horn-like objects extending from his upper back.

Tarnak was the King of Monstrous Humanoids and the Monarch of the Iron Body. Tarnak was a handsome young man with slick blond hair and green eyes. He wore a long white coat with a bright blood-red collar, golden shoulder pads, black pants, black shoes, small earrings, white gloves, and a plain gray T-shirt.

The White Tiger Guild is one of the top five Korean guilds. It is active in the Seoul Metropolitan Area and has an unique practice of training their new recruits by having them go on raids with the guild's stronger members into low-ranking gates.

The Scavenger Guild is the strongest guild in America. Due to how large it is, the guild operates all over the country and sends its members overseas from time to time to other countries that are incapable of clearing gates on their own. The Guild Master of the Scavenger Guild is Thomas Andre.

Assassins are hunters who specialize in both speed and close-range combat. Assassins are swift and agile, and are considered to be the fastest hunters around. They typically fight with smaller weapons like daggers or hidden blades. Assassins tend to have weaker defenses.

Mages are hunters who specialize in sorcery and magic. Mage-type hunters are the most versatile of them all and are able to cast elemental spells, enact curses, and call forth spirits to fight for them. As a result, a large portion of their abilities are projectile attacks. However, since they attack from a distance, mage-type hunters are generally at a huge disadvantage in close combat.

Fighters are hunters who specialize in melee combat, striking a balance between offense and defense, and can adapt to a variety of combat scenarios. Fighter-type hunters excel in delivering substantial damage through close-range combat. They are characterized by their strong offense, effective defense and endurance, making them formidable brawlers in melee combat.

Rangers are hunters who specialize in archery magic. Although both mages and rangers attack from a distance, they differ in that rangers specialize in physical and not magical attacks. As a result, they generally wield bows or crossbows and are tasked with covering the blind spots of their allies during raids. Unfortunately, this also means that they are at a huge disadvantage in close combat.

Healers are hunters who specialize in healing magic. Unlike other classes, healers usually serve as support and rely on damage dealers to protect them in battle. Although they mainly specialize in healing other hunters of their injuries, healers are also able to cast buff magic in order to enhance both their own abilities and the abilities of their teammates.

Tankers are hunters who specialize in defense. As they specialize in defense, tankers generally carry shields and wear heavy armor and are tasked with shielding the rest of the team during raids so that the other hunters can perform their roles. Compared to other classes, tankers are much more durable and are able to take much more punishment in battle before going down.

Kamish was an immensely powerful magic beast and the boss of the first S-Rank Gate that ever opened. He was responsible for single-handedly devastating the American west coast area and massacring all but five of the S-Rank Hunters who were fighting against him. As a result, Kamish is regarded as humanity's greatest calamity. Kamish was an enormous red western dragon with gray horns, glowing yellow eyes, a light brown underbelly, and a long red, whip-like tail.

Hwang Dongsoo was a Korean-American S-Rank Hunter and the younger brother of Hwang Dongsuk. Hwang was a large and muscular man with black hair in a buzz cut.

Spiritual Body Manifestation is a unique skill limited to Rulers and Monarchs, with the skill being able to transform the user into their 'fully-powered' form.

To prevent the loss of human life as much as possible, a dungeon must be cleared within seven days. If it is not, then it will undergo a dungeon break, meaning that the monsters inside the dungeon will be able to cross over to the human world and attack the civilian population.

The Absolute Being was a god and the creator of both the Monarchs and the Rulers. The Absolute Being was a gigantic man with long silver hair, pale white skin, and blank yellow eyes.

The Ant King was an immensely powerful magic beast and the hidden boss of the Jeju Island S-Rank Gate. He was also one of the most powerful monsters to fight against humanity. The Ant King was a huge humanoid ant with a black armored exoskeleton, glowing red eyes, sharp claws, two small pincers extending from his abdomen, and two transparent ant wings.

The Ant Queen was the boss of the Jeju Island S-Rank Gate and the mother of the Ant King. The Ant Queen was an enormous ant with chitinous white armor and pale lavender eyes. She deliberately bred the Ant King into a soldier strong enough to take down S-Rank Hunters even as powerful as Goto Ryuji.

Goto Ryuji was the strongest hunter in Japan and the Guild Master of the Draw Sword Guild. Goto was a handsome and muscular man with shaggy black hair and a neatly trimmed black beard. As the greatest hunter in Japan, Goto was one of the strongest S-Rank Fighter foreign hunters (aside from the National Level Hunters).

The Draw Sword Guild, also translated as the Blade Guild, was the strongest guild in Japan and the second largest guild in Asia. It has 11 S-Rank Hunters, including Goto Ryuji.