According to the author, Subaru's birthday is April 1, and his birth flower is a Gypsophila elegans, or annual baby's breath. Subaru has been ranked among the five weakest characters in Re:Zero.[8] Subaru is surprisingly talented at sewing. In the later arcs, his skill improves to the point where he can even make stuffed toys. Subaru had once cross-dressed in his old world under the name "Natsumi Schwartz". He has used this alias and cross-dressed on a few occasions in the new world. "Schwartz" means "black" in German. Like his parents (Natsuki Kenichi and Natsuki Naoko), Subaru has a personal bottle of mayo back home. The reason why Subaru tapped Crusch's hand instead of shaking it in episode 27 is because he was shy about shaking a girl's hand. From the very moment Subaru was summoned to another world, he subconsciously knew he would never return to Japan. Subaru's phone ringtone is "Yoake no Michi" from Dog of Flanders. In a Q&A, the author stated the chance of Subaru not dying in an arc is 0.[9] Even before meeting Emilia, Subaru preferred girls with silver hair. Subaru has a personal ranking of his friends and he would use Return By Death if one of them died. According to the author, the reason he made Arc 3 was for Subaru to say two lines. The first one being "I hate myself" and the second one being "I love you" (to Emilia).[10] In Arc 6, Subaru is revealed to regularly partake self-harm, scratching his arms until he bleeds, biting his lips, et cetera. Shamak was in fact more useful to Subaru than Invisible Providence is, according to the author himself. Following the incident involving Rem, Greed and Gluttony, Subaru visited Rem daily, discussing his day with the sleeping girl, without fail. Many of the Sin Archbishops such as Petelgeuse seemed to suspect that Subaru is supposed to hold the seat of Pride in the Witch Cult, with both Petelgeuse and Rui claiming that the vacant seat belonged to Subaru, however, it is currently unknown if this is true or just deluded gibberish from the Sin Archbishops. Subaru is the Sin Archbishop of Pride in the Ayamatsu IF, but the short story is non-canonical to the mainline story. In both the Light Novels and in the web novel, Subaru has his own named chapter. In the web novel, Subaru was in fact able to read Petelgeuse's Gospel. This event, however, was cut from the Light Novel, for reasons yet unknown. Furthermore, the reason why he was able to do that, remains unknown. Subaru considers Wilhelm to be the very ideal of a person and a man,[11] and is the person Subaru respects the most in the new world.[12]

Subaru is first seen at a local Japanese convenience store, buying consumer goods. After leaving the store, he somehow ends up in a fantasy world, after the atmosphere around him distorts itself. Confused by the happenings around him, Subaru later realizes that he has been sucked into another world. Back in his original world, Subaru was the only son to two odd, but well-meaning parents, Kenichi and Naoko. From a young childhood age, Subaru idealized his dad in particular, a popular man in his community who was highly talented in whatever he did, a loving father who prioritized his family above everything else, and had a boisterous personality that charmed anyone he met. Kenichi was everything he wanted to be and growing up around him had a huge influence on Subaru's life. Taking pride in being his son, Subaru worked to live up to the expectations that came with that in his mind. For a time, he achieved this, as Subaru found himself smarter, more physically able, and popular than his peers. When he received praise, Subaru would of hear how it was expected of him being Kenichi's son, which made him feel special and entitled to a sense of superiority. However, as the young boy's small world started to gradually expand upon entering middle school, Subaru would come face to face with limits of his own ability. Suddenly, he found people who were becoming smarter and faster than he was and, in general, being better at the things he used to be. He felt as if he was slowly losing his place and began to harbor a deep sense of shame at letting down his parents and fear of everyone leaving him for failures, doubt and self-loathing began to develop in his heart. But rather than prioritizing getting better at those things to combat his anxieties, Subaru instead placed more importance on doing daring and outrageous things to maintain his fragile dignity and keep himself the center of attention. However, the more reckless Subaru's actions became, the fewer people wanted to be around him. Yet Subaru continued to deceive himself and believe his own lies because as the son of his seemly indomitable father, he couldn't be seen as a failure. Eventually, one day, Subaru noticed he no longer had any friends and in his loneliness, Subaru realized he wasn't anyone special. From then on, the comparisons between his father and himself turned into a curse that wounded and suffocated him everywhere he went, yet his strong admiration for his dad made it impossible to show that pain to anyone. Eventually, he stopped trying to stand out and when high school came, he found himself in a new environment where no one knew his past. Seizing this opportunity, Subaru tried to build new interpersonal relationships, but he had no idea how to be himself around others and instead only ended up emulating his father, his only frame of reference which instead led to others to treat him as a clown and classmates simply ignored his existence altogether. One day, Subaru skipped a day of school out of lack of enthusiasm, which slowly turned into a constant thing until at one point, he hadn't been to class for three months. When out of public spaces, Subaru felt liberated, but more than that, his own degradation meant people would start distancing him from Kenichi and in a twisted sense of hope, his parents come to acknowledge him as worthless and cast him aside in self-abandonment. After being summoned to a new world, he saw this as a chance to make a fresh start; however, he didn't change as a person. He decided that he would save Emilia, and eventually, he was exposed for what he was, a person forcing their feelings on someone else, and that his white-knighting doesn't work out in the real world. He thought of himself as the hero of his own story, but was faced with reality when he didn't have the overpowered abilities of a usual protagonist, he however chose to ignore that he wasn't the hero and that the world would go on with or without and tried to force his way into Emilia's affairs, and in the process making a complete fool of himself. The world then proceeded to show him how weak he was, and that he couldn't save anyone, after being utterly broken, he wanted to run away but was however stopped by Rem. This became the turning point for his character; he truly made an effort to change himself rather than expect that as the supposed protagonist, everything would work out, which it didn't before as he had to watch the results of his failures and see the people he cared for die over and over again. Eventually after hitting his breaking point and coming to terms with his inter conflicts with some encouraging words from Rem, Subaru began reflect on his actions and take step to amend his broken relationships, ultimately learned to be better considerate of Emilia's feelings rather than just forcing his in expectation that she would reward him. Subaru indeed became a changed character, and he also now tries to live up to the expectations of a hero that Rem had for him. According to the author, after Subaru went missing (was transported to the Kingdom of Lugunica), a police investigation was launched but ended up empty-handed.

Abilities Return by Death (死に戻り Shinimodori): Subaru's trump card and the most recognised ability from the series, Return by Death, allows Subaru to return to an unspecified, unpredictable and uncontrollable "save point", that was set some time before his death. It happens instantly after his life was taken, there's no lag between the point of death and the point of resurrection, and there is no known limit to how many times Subaru can "Return by Death", making this ability an effective way of permanently bypassing death as it currently stands in the latest chapter of Arc 7. To Subaru, it looks exactly as if someone switched camera angles inside his head and the sudden influx of new information and sensations often makes him feel dizzy and confused. In Volume 11, it is revealed by the Witch of Greed that Return by Death is actually an Authority[2] given to him by the Witch of Envy[3] in order to prevent him from being shackled by mortality, granting him a means to challenge fate itself and beat impossible odds in which he's destined to die in the most cruelest of ways.[4] Having said that, Subaru's application of this Authority – namely to use it to save his friends and loved ones from their untimely demises – is something willingly and consciously done by Subaru alone.[5] This often results in Subaru being given almost absurdly short times between his save points and deaths, and at times, even preventing him from saving some of his friends such as when Rem's name and memories were eaten by the Sin Archbishop of Gluttony in Arc 3's second interlude, where Subaru was given a save point hours after Gluttony and Greed's attack on Rem's carriage convoy. Penalties: Subaru is unable to reveal his ability to others. There are three primary penalties for attempting to do so: If Subaru was to tell Emilia about his ability, it would end in her heart being crushed by the Witch's hand. The exact explanation about this penalty is currently unknown, as according to the author, this penalty affects Emilia and no one else.[6] It will increase the density of Witch Factor at least for a short time, which will draw any Demon Beasts in the immediate area to him like moths to a flame. Future Recollection: The trait that makes Subaru so dangerous is without a doubt his ability to recall the futures he had experienced through Return by Death. The fact that he can recall the events of the previous loops he had died in, means that Subaru inherently knows the rough actions the people around him will take, almost like a form of precognition. As he usually tries to do different things every time he returned to life, Subaru is able to gather more intel on how his allies and opponents behave under specific conditions, allowing him to predict their movements and plan strategies accordingly. Although he is average at best in terms of intellect and strategic planning, Subaru's recollections of failed futures as well as his basic problem solving abilities essentially turned Subaru into someone who expertly manipulates the events around him. Within a year and a half of arriving to the other world, Subaru had helped orchestrating the downfall of the Sin Archbishops of Sloth, Greed and Gluttony, the Bowel Hunter Elsa Granhiert, and two of the Three Great Demon Beasts—the Hakugei and the Oousagi. His recollection of the future also allows him to forge better relationships with those he considers allies, allowing him to amass an impressive web of political connections and friends in high places. Authorities (権能 Ken'nō): Subaru is currently able to use two Authorities: Sloth and Greed. According to Echidna, Return by Death is also an Authority that seems to have been gifted to him by Satella, but no actual conclusions of which Sin it represents have been drawn yet. Authority of Sloth (怠惰の権能 Taida no Ken'nō): After the death of Petelgeuse Romanée-Conti, Subaru became the current holder of the Witch Factor of Sloth, enabling him to develop an Authority of Sloth. When Natsuki Subaru killed the Sin Archbishop of Sloth, he absorbed the Witch Factor of Sloth that resided within the madman for the past century. Strangely enough, Subaru's Authority of Sloth manifested itself in almost entirely the same way as Petelgeuse's did, at least appearance-wise. Unlike Petelgeuse, who called the power the Unseen Hands, after Echidna synchronised his body and the Witch Factor of Sloth, Subaru manifested an Authority of Sloth and chose to call his version of the Authority "Invisible Providence". It is a power that allows Subaru to summon a single invisible hand-like appendage from his chest and move and extend it telekinetically. If Subaru focuses enough, he can even make the hand phase through matter as though it wasn't there. Subaru's version of the Authority of Sloth is far less powerful than both Petelgeuse's and Sekhmet's Authorities of Sloth, as although Petelgeuse for instance could summon roughly one hundred hands at his maximum potential with little effort, Subaru can only summon a single hand with minimal range and damage output. However, as a side effect of calling forth his Authority, Subaru's internal organs begin to flair up, he feels his soul becoming more and more tainted, and he is assaulted by a violent coughing attack accompanied with him throwing up smaller amounts of blood.[7] Authority of Greed (強欲の権能 Gōyoku no Ken'nō): After the death of Regulus Corneas, Subaru became the current holder of the Witch Factor of Greed, enabling him to develop an Authority of Greed. Cor Leonis (コル・レオニス Koru Reonisu): When Reinhard van Astrea killed the Sin Archbishop of Greed in the Crusade against Greed during Witch Cult's assault on the Watergate City of Priestella, Subaru absorbed the Witch Factor of Greed which resided within the white haired calamity for over a century. He manifested Cor Leonis towards the end of Arc 6. Similarly to Regulus' Authority of Greed, Cor Leonis has two phases; its base form and Second Shift. The base shift of Cor Leonis allows Subaru to take on the physical and mental burdens and fatigue of people he himself considers allies, effectively eliminating problems such as injuries or lack of dexterity for his comrades in combat. He is also able to shoulder fatal injuries and save his allies' lives, however, at a cost of receiving the same wounds himself as his body naturally reproduces the sources of pain he suddenly receives; a deadly side effect which can easily kill him, if ignored. When using this phase, Subaru is able to locate his allies' position and status as he sees pale white dots, wherever they're located; though his allies must also consider Subaru their own ally, otherwise Subaru will not be able to sense their location – during the very first chapter of Arc 7, Subaru tried to locate Rem's location but was unable to, as due to her loss of memories she did not recognise him as her ally. It only works on people he recognizes as his friends and allies. Second Shift (セカンドシフト, Sekando Shifuto): Second Shift, also known as Division of Labour (負担の分配, Futan no Bunpai), works very similarly to Regulus' very own Lion's Heart, in a sense where Subaru can divide the burden between the allies of his choosing. He can freely regulate how big of a burden he'll employ on each person, kind of like opening or closing a tap. Naturally, the same side effects will apply to each and every bearer of the shared burden, meaning their lives rest in Subaru's hands for the entire duration. The only condition for using the Second Shift is that the person Subaru wants to share his burden with, must be willing to accept his burden and open their heart to Subaru. Curses (呪い, Noroi): Subaru has been afflicted by two curses: a curse from numerous Wolgarm Demon Beasts and a curse from an unnamed Dragon's blood. Wolgarm Curse: In Arc 2, Subaru was bitten by numerous Wolgarms that attempted to drain his mana with their curse. Although they were all slain before the curses were activated, the curses were too numerous to be removed, so he was forced to keep the curses inactive within his body. Curse of the Dragon's Blood: After his fight with the Sin Archbishop of Lust and getting afflicted by the curse within her Dragon's blood, Subaru's entire right arm has been covered in thick and pulsating black veins. During Arc 5, it was this liquid that miraculously healed his shredded right leg, after his initial fight with the Sin Archbishop of Greed. Roughly three months later, during the events of Arc 7, Subaru lost his right wrist against a giant Demon Beast snake. Immediately after falling unconscious, the arm was miraculously healed, forming an entirely new and fully functioning arm, covered in thick black and pulsating "skin". It was noted by Subaru that the new skin was rubbery to the touch and not as sensitive to the touch as the other parts of his body. The pseudo-skin was also easily peeled off, revealing fresh skin underneath. Magic User (魔法使い Mahō Tsukai): In the world Subaru was summoned to, individuals were capable of manipulating magical energy known as mana because of a "gate" that existed within every person's body. This gate would draw mana into a body as well as expel it out, functioning as a kind of faucet for magical energy. Each person possesses a different elemental attribute that allow them to produce magical spells related to that element. Of the six elements, Subaru's designated element is Yin Magic, a fairly rare attribute. Although he was a novice, Subaru had the capability to cast very basic-level Yin Magic spells. However, after overusing his gate, it became defective, meaning he could no longer cast any kind of magic. He is still able to use Yin magic through Beatrice, though Beatrice has run out of her mana supply when fighting the Oousagi, rendering both unable to use any kind of spell that isn't too complex. According to the author, Subaru could learn how to use other types of magic if he dedicates his life to that. Spirit Affinity: Subaru has a rare innate gift to form contracts with spirits. Spirit User (精霊使い Seirei Tsukai): Subaru is contracted with the artificial spirit Beatrice, though according to her, he isn't a true spirit user. She also has a terrible mana consumption rate and formerly got around this by draining mana from people in the mansion using the library as a medium. After their initial fight against the Oousagi, Beatrice depleted her mana reserves in its entirety, meaning she's barely able to cast basic level magic. As Beatrice's contractor, Subaru's condition and whereabouts can be sensed by her via their connection, although he is unable to do so. Furthermore, he is capable of remotely calling Beatrice out if he focuses enough on his link with her. Like Julius, Subaru is also considered to be a Spirit Knight (精霊騎士 Seirei Kishi). As she is an artificial spirit, she also has several conditions Subaru is forced to follow: Subaru cannot form a contract with other spirits. Beatrice cannot restore mana on her own. Beatrice cannot use the mana in the atmosphere. Beatrice can only drain mana from Subaru. Spirit Arts (精霊術): Subaru is capable of using spirit arts with Beatrice, and is thus able to use Yin Magic with her aid. He has also created a number of original spells with her, unique to the pair. He is able to use: One of the most basic shadow magic spells, and the only spell Subaru could use until the collapse of his gate, was "Shamak." When cast, a blanket of black smoke would erupt from the user that would cover a significantly large area. Any target engulfed by the smoke would completely lose their spacial awareness. Under the spell's effect, the only thing the target could sense was the ground under their feet and any damage done to their body. Although it was a low-level spell, it proved an effective smokescreen when retreating or for masking attacks. As it was the only spell he was capable of using, Subaru was particularly fond of Shamak. he used it a number of times, and even came to grow attached to it, calling it "Shamak-san." He is still able to use the spell through Beatrice. Minya (ミーニャ): Subaru can create stakes made of crystallized mana covered with light purple flames as an offensive attack via spirit arts. They are strong enough to penetrate defences. Any stakes in the air explode and release smaller stakes that fly in all directions which then rips targets apart. El Minya (エル・ミーニャ): The spell works very similar to normal Minya. The only difference is the number of stakes, which increase to around 40. Murak (ムラク): Subaru reduces the effects of gravity. Just by jumping lightly, a person can jump as if they had springs. If Subaru wishes to, it can also be used to fly, although Subaru will get blown around by the wind like a leaf, but they won't flip around in midair. EMM (E・M・M; エミリアたんマジ女神, Emiria-tan Maji Megami; "Emilia-tan is Seriously a Goddess"): EMM is an "absolute defence magic". Beatrice uses Yin Magic to interfere with the time and space around Subaru, and while he can't move during activation, he experiences no interference from outside the barrier. It is similar to Regulus Corneas's Little King, but does not have the same risk, renders Subaru and Beatrice unable to move and can be used until mana runs out. EMT (E・M・T; エミリアたんマジ天使, Emiria-tan Maji Tenshi; "Emilia-tan is Seriously an Angel"): EMT is an "absolute negation magic". It is a spherical field several ten meters long with Subaru and Beatrice at the center is created, which negates effects from mana within it. Julius remarks that it is useful against mages and those who use mana to assist their techniques. However, the magic only negates the use of mana, and so it has no effect against opponents who fight without it. Non-Stop Abyss (ノンストップ・アビス): Non-Stop Abyss made its debut in the non-canon Isekai Quartet Movie. Likely using Beatrice's Door Crossing magic, this combination technique connects a miniature handheld door to a much larger door. By using this technique, Subaru and Beatrice can move someone from the smaller to the larger to quickly transport them from point A to point B. Even if the opponent is considerably larger than the mini door, it can still absorb them and teleport them to the other. Cocytus (コキュートス, Kokyūtosu): Cocytus is a large scale spell made out of two combined elements, which was used by Subaru and Emilia during their fight against the Oousagi. While Subaru used Yin Magic to form some sort of a barricade around the Demon Beasts to prevent them from escaping, Emilia used Fire Magic to carefully apply magical energy to the already-casted Minya spell, creating an icy cage and lifting the cage, the Demon Beasts and the ground itself high in the air. Melee Fighter: Subaru grew up an active athlete in his early years in his school, and although he drifted from partaking in any school activities prior to his transportation to the new world, he nevertheless still maintain a strict fitness regimen and as a result, he has raw athletic prowess and a high degree of physical strength, reflex and stamina. Despite all that, Subaru is not a skilled as the very vast majority of the warriors he has met in his two years of living in the New World and can barely hold his own against normal people–according to the author, a fistfight between Otto and Subaru would always end in Otto's win. To somewhat make up for his fighting shortcomings, Subaru has sharp reflexes and demonstrated it when he was able to dodge Felt's confused swings when she confused him for an intruder and Rem's flail attack in the second attempt for his life. Sword Skills: He did kendo in middle school for a bit, so he has some basics in swordsmanship. After his humiliating defeat at the hands of Julius, Subaru received some rough sword training, under Wilhelm van Astrea at the Karsten mansion, Subaru unlocked a basic grasp on swordsmanship that was helped by the kendo he did when he was younger. However, it should be mentioned that despite the combative skills Subaru picked up from his time in Japan as well as his time in the other world, he was still a low-level combatant overall who would lose to almost every opponent he faced in terms of battle power as he's completely talentless with a blade and is unable to hold his own against anyone who's at least fairly skilled with a sword. Subaru personally mentions that he is able to bench 80 kg (176 lbs). Before being teleported into the new world, he maintained a fitness regimen of one hundred push-ups, sit-ups, and squats a day, allowing him extremely above average physical ability, especially for a hikikomori whose diet consisted of mostly convenience store items. Parkour and Survival Skills: During the following year after the incident at the Sanctuary, Subaru learned the basics of parkour from Clind and began training himself. The butler also provided Subaru with essential survival skills, which came in handy to Subaru in the start of Arc 7. Deductive Ability: Arguably Subaru's greatest asset, aside from Return by Death, is his own mind. Though he wasn't blessed with particularly noteworthy intelligence, he has always had great deductive ability, something he prides himself on. This works well with his time-looping, as the information it provides would be useless if he wasn't able to think and act on it to find the optimal course of action. Both Garfiel and Reinhard have complemented Subaru's strategic ability. Apostle of Greed: For partaking in the Trial of the Sanctuary, Subaru was given the mark of the Witch of Greed Echidna that indicated him as an Apostle of Greed. Because of this title, Subaru was capable of commanding the many replicas of Ryuzu Meyer created by Echidna centuries ago. The replicas were compelled to follow any order they were given, regardless of their own thoughts on the matter. This gift from Echidna essentially bequeathed Subaru with a small army for a time, however, the Witch of Greed eventually took away his title, meaning that he became unable to command Ryuzu's replicas. Equipment Guiltywhip: Subaru uses a whip as his main weapon. Like his parkour, Subaru learned the basics of using it from Clind. In the Light Novel, it was revealed that his preferred whip was made of the Demon Beast they fought in Arc 4, the Jet Black King of the Forest Guiltylowe. He named said whip the Guiltywhip.