|Age||14 (start of the series)|
|Occupations||UQ Holder #11|
|First Appearance||Chapter 3|
|Voiced by||Yuki Hirose (Japanese)|
Kalin Coates (English)
While identifying himself as male, Kuroumaru is actually genderless; meaning that he does not posses the physical sexual properties of either male or female, due to his demonic lineage as part of the Yatagarasu, who grow genderless until their 16th birthday, whereupon they can choose to either become a male or a female. While possessing a decidedly feminine appearance, which results in him being constantly mistaken for being female, Kuroumaru has expressed a wish to become a male at his 16th birthday; though later realizes that he might want to be a female due to his feelings toward Touta ; feelings that Kuroumaru perceives that take a solider shape when his body begins to turn into a woman.
Kuroumaru has a slim figure and very long black hair which is tied in a side-ponytail and split at the front as long bangs that sometimes covers his left eye. Preferring to be identified as male, Kuroumaru normally wears a formal white business shirt and tie with black pants underneath a black long coat that effectively hides his body shape. He is usually seen carrying his sword around wherever he goes, although he can also use Magic to summon the weapon should it not be on his person.
Kuroumaru so far has demonstrated a kind, and easy-going personality, and is quickly able to make friends. Originally, he held his clan to heart, although they may not have treated him kindly, but he was loyal to their every command.
After joining Touta he seems to not be as emotionally reserved. He shows traditionally feminine attributes when speaking to others, but becomes annoyed when he is called a girl. This is due to him not having a gender as his clan does not gain one until they are 16, leaving him preferring to be seen as a male. However his feelings conflict with his desires, leaving him confused at time.
At one point, as a member of a clan of immortal hunters, Kuroumaru is sent to kill Evangeline A.K. McDowell. He is told not to return should he fail his mission. It is then revealed that the rest of the clan resents Kuroumaru for his "cursed body" as Kuroumaru overhears them talking about his mission, noting that if he succeeds, they will benefit from it and if not, they'll at least get rid of the nuisance that they consider Kuroumaru to be.
UQ Holder arcEdit
Kuroumaru appears for the first time initially meets Touta when they are both bathing and Touta accidentally stumbles upon him bathing. Touta evades Kuroumaru's sword and asks for him to calm down, and presumes Kuroumaru for a girl, due to his feminine figure, causing him to get punched by Kuroumaru. After they both calm down, Kuroumaru tells Touta that no one other than him has ever evaded his sword, and formally introduces himself. Touta does the same, and discovers that Kuroumaru is a resident from space, and immediately requests that Kuroumaru becomes his friend. Touta later discovers that Kuroumaru is looking for 'Evangeline A.K. McDowell', otherwise known as Yukihime. Touta explains how the person Kuroumaru is looking for is his traveling companion, and Kuroumaru then makes the discovery that Touta himself is not human. He tells Touta that it is a shame, since he felt that he and Touta could have been friends, and brandishes his sword at him. Kuroumaru then attacks Touta using the Shinmei-ryū fighting style, but Yukihime intervenes by catching Kuroumaru's blade, and stabs him through the chest with her hand.
Touta starts shouting at Yukihime for doing that to Kuroumaru, however she tells Touta to look closer at his body, and upon further inspection, it is revealed that Kuroumaru is an Immortal, as the wound in his chest heals. Kuroumaru regains consciousness after Touta attempts to 'check' his gender, and requests a duel between him and Yukihime for the sake of his clan. Yukihime tells him that if he is able to best Touta in battle, she will grant him the right to fight against her. Kuroumaru accepts and begins to battle the unwilling Touta, who is attempting to calm the both of them down during their discussion. Touta then tells Kuroumaru that he will fight seriously if Kuroumaru agrees that he will listen to whatever request Touta gives of him, and Kuroumaru accepts. Touta ultimately beats Kuroumaru in battle, and asks for the two of them to become friends.
The First Mission arcEdit
After joining UQ Holder, Kuroumaru and Touta are sent to their first mission with Karin, another immortal. Before leaving, Karin enters the other two's room, and accidentally sees Kuroumaru naked while changing. Karin asks why Kuroumaru never said she was a girl, and Kuroumaru denies it. Karin lets it pass and they leave for the slums, where a church in which several children live in is threatened by landsharks. They encounter a cyborg known as "demolition man". Karin defeats him while revealing a strange tattoo on her back, and does not appear to be hurt although she is pierced by many spears. The three of them stay for a while. Kuroumaru discovers that Touta is learning instant movement from a passing-by skilled martial artist. Suspicious, Kuroumaru tells Karin this and she says she will get the grunts to investigate. Karin then asks Kuroumaru whether he likes Touta. Looking panicky, Kuroumaru denies it and Karin asks again whether he is male or female. Kuroumaru explains he is genderless.
During this arc he fought against Asura, a member of Ala Alba while trying to imprison Fate. The fight was left unfinished as Kirie had awoken and then sent them back into the past where he asked Fate a question about if there is a time limit for when Touta is needed to free his grandfather, Negi Springfield.
Kuroumaru joins Touta and others to get information from Yukihime about their upcoming job. He learns that they will infiltrate a private boarding school in order to investigate a hidden immortal. However, much to his shock, he finds himself wearing a girl uniform, thanks to Karin. He argues that all he wants is to be friends with Touta when Karin insists to be more aggressive towards him. Kuroumaru changes to a boy one and eventually arrives at Amano-Mihashira Academy City along with others, excited as he has never been to school before. Both him and Touta are then seen being introduced to their class, as well as playing basketball, where Touta warns Kuroumaru not to stand out. The two head for lunch, but are surprised to see students hurrying to get the food they want. Touta and Kuroumaru soon meet up with Karin and Ikkuu, with the former explaining that the immortal has already killed two people. Kuroumaru then witnesses Michiel's arrival, soon realizing that he is talking about magic just as he claims Kuroumaru and others to be non-wielders. Kuroumaru watches as Touta challenges Michiel to a duel.
He and Touta end up sharing a room with Santa, whom they are informed by Sayoko is an revenant, leading to a confrontation. Sayoko soon reveals her true colors as the murderer and when they try to stop her, Kuromaru ends up being possessed by her power and made to fight Touta until Santa calms her down. They return to the past where he apologizes for turning against him.
Mahora Preliminaries Arc EditKuroumaru is seen bathing with Kirie saying the enemy of a maiden is a enemy of mine. Kirie calls Kuroumaru a newbie. Tota ask what are they doing.
Skills and AbilitiesEdit
Kuromaru is an immortal through experimentation and utilizes Ki for offense and defense. Even without it, he's in peak physical condition as mastering Ki requires that the body be strong and has reached a limit that can be surpassed. However as his transformation into a woman continues, Kuroumaru appears to have his physical strength diminished.
Regenerative Healing Factor: Kuromaru has undergone a sorcery-induced body modification that gives a "Immortality Level: B" regeneration ability . His body registers any damage done to it and heals the wound at a supernaturally fast rate, which has been compared to werewolf's ability to grow fur. However, if he sustains too much damage too quickly, then he is immobile until it can heal. Likewise, anything wedged into his skin has to be removed.
Master Swordsmanship: Kuroumaru uses a fighting style called, Shinmei-ryū, a famous sword style meant to slay monsters and exorcise spirits. Shinmei-ryū style uses ki to increase the strength of attacks and produce different effects. They are generally elemental attacks (lightning, wind, and earth are common elements) or normal empowered physical feats.
- Shundō (瞬動, Instant Movement) - A movement technique that allows the user to move faster than the eye can follow. This is used by concentrating ki or magic power into the feet to get from point A to point B in the least amount of steps. It's important that when going from point A to point B that you hold to the ground with the inside of your feet or you will simply trip.
- Clone technique: He can create clones for use in battle. 
Kuroumaru is a very skilled swordsman and practitioner of the Shinmei-ryuu(神鳴流 ,Shinmei-ryū, "Gods' Cry School") Fighting style. It makes him an effective combatant against ghosts and spirits like Santa. So far he has demonstrated the following abilities:
- Stone Cutting Sword (斬岩剣, Zanganken): 
- Stone Cutting Sword Seven-fold Speed (斬岩剣七連倍速, Zanganken Nana-ren Baisoku) 
- Evil Cutting Sword, Second Strike (斬魔剣 弐之太刀, Zanmaken Ni no Tachi): 
- Air Cleaving Flash (斬空閃 ,Zankūsen): 
- Radiant Sword Wind, Inferno Wall (剣風華爆焔壁, Kenfūka Bakuen Heki): 
- Rising Silver Dragon Thousand Chrysanthemums Glowing Dew (昇銀竜千輪菊光露, Nobori Ginryū Senringiku Kouro): 
- Earth-Splitting Four Oni Exorcism(地裂四鬼祓い, Chiretsu Shiki-barai): 
- True Thunderlight Sword (真・雷光剣, Shin - Raikōken) 
Note: So far, all moves have been performed with the Iaido Stance (Sword beginning within its sheath).
- Gladiarium Neutrale: Kuroumaru's Pactio card, he received the card by having a contract with Touta with the help of Albert Chamomile.
- Tenka Goken: Mikazuchi Munechika Replica - Tatami no Mai: The Pactio card ability is summons a bunch of replicas of a famous sword around Kuroumaru.
- Summoned Swords: Kuroumaru seems to have a magical supply of swords which he can summon at any time.
- Fire Conjuration: Kuromaru can turn his Ki into fire to use as a light source using a pen. He states this isn't an app, but something he was taught as tradition.
- Inatsurubi no Katama - Magic Bind (稲交尾籠 くくり方陣, Inatsurub no Katama Kukuri Hōjin) 
- His fighting style is the same as that of Setsuna Sakurazaki from Negima! and that of Motoko Aoyama from Love Hina.
- Rumors state Kuroumaru is the deuteragonist and dubbed as the "heroine." Although, the author has stated that both Touta and Kuroumaru are the protagonists, except that the former has more of a lead role.
- Kuroumaru is the first character to make a Pactio contract in the series.
- Mikazuchi Munechika is one of the Tenka Goken, a group of five famous japanese swords.
|Kuroumaru vs Yukihime||Loss|
|Kuroumaru vs Touta||Loss|
|Kuroumaru vs Gengorou (Anime only)||Loss|
|Kuroumaru & Touta vs Jinbei (Manga only)||Loss|
|Kuroumaru vs Gengorou (Anime only)||Win|
|Kuroumaru & Touta vs Monsters (UQ Holder Test, Manga only)||Won|
|Kuroumaru vs Kaito & Nagumo||Loss|
|Kuroumaru vs Asura||Interrupted|
|Kuroumaru & Touta & Ikkuu vs Santa||Loss|
|Kuroumaru vs Sayoko||Loss|
|Kuroumaru (Zombified) vs Touta||Draw (i)|
|Kuroumaru & Santa & Kirie vs Tena Vita (Manga only)||Draw (i)|
|Kuroumaru & Touta vs Ruin Ishkur||Won|
|Kuroumaru vs Xingzi Chao & Asura||Won|
|Kuroumaru, Touta, Santa, Karin, Ikkuu, Yukihime & Fate VS Mage of the Beginning, Negi Springfield, Albireo Imma, Jack Rakan, Yue Ayase, Nodoka Miyazaki & Tena Vita||Interrupted|
(i) - interrupted/incomplete