Kiyohiko

Biodata

Power Progression

Background / History

Previous Life and Transmigration

Kiyohiko was a twenty-year-old medical intern who died suddenly after working day and night. He transmigrated into a demon’s body on Mount Fujikasane and recognized the setting after encountering the Hand Demon. His knowledge of Demon Slayer was incomplete because he had watched little of the anime 1.

He arrived with exceptional regeneration and the Bond System, which rewards stronger interpersonal bonds. Hoping that befriending the original story’s main characters would yield better rewards, he set out to find Tanjiro Kamado when Final Selection began 1.

Final Selection

Kiyohiko refused the Hand Demon’s proposal to eat the candidates and escape together. He instead searched the forest, where a prank frightened Zenitsu unconscious and triggered a sleeping Thunder Breathing attack that nearly severed Kiyohiko’s head. After regenerating, he recruited Zenitsu’s hearing to help locate Tanjiro, but they first found a dying candidate whom Kiyohiko healed by taking on his wounds 1 2 3 4.

When Tanjiro became trapped by the Hand Demon’s arms, Kiyohiko shielded him and was impaled through his abdomen, shoulder, and thigh. He then immobilized an arm long enough for Tanjiro to decapitate their opponent 5 6.

Despite his depleted condition, Kiyohiko healed two more dying candidates. Anticipating that hunger might overwhelm him, he told Tanjiro to cut off his head if he attacked them. Tanjiro instead knocked him unconscious with a headbutt when he began losing control 6 7.

The candidates he had saved later joined Tanjiro and Zenitsu in protecting him at the selection’s exit. Their defense completed a bond event and earned him rewards while he remained unconscious 7 8.

Acceptance by the Demon Slayer Corps

Kiyohiko awoke after two days restrained in a dark room at the Butterfly Mansion. Shinobu explained that the Master had ordered her to keep him alive for observation, though she remained openly hostile toward demons 9 10.

At the Hashira meeting, Sanemi Shinazugawa exposed him to Marechi blood to provoke an attack. Kiyohiko resisted despite severe distress. Kagaya Ubuyashiki accepted this as proof that he retained reason and entrusted his supervision and treatment to Shinobu; six newly selected Corps members also vouched for him 12 13.

Life at the Butterfly Mansion

Kiyohiko received a secluded, wisteria-free room and animal blood, while Aoi supervised his daily routine. Shinobu subjected him to examinations, blood collection, medicine, and regular combat training 16 18 19 38.

His concern for Shinobu deepened after transferring a wound from her poisoned body and discovering how severely her blood damaged his regeneration. He challenged her disregard for her health and later used a deliberately transparent story about a demon and a “bad woman” to offer to share her burdens. Shinobu accepted his offer to try helping her 20 21 26.

His treatment of a critically injured Slayer caused another dispute: Shinobu forbade reckless use of his Blood Demon Art, while Kiyohiko argued that his regeneration made the injuries survivable. He eventually apologized for ignoring her feelings and told her she was the most important person to him 41 43 46.

After their reconciliation, Kiyohiko began telling Shinobu about his former medical work without revealing his reincarnation. She later fulfilled his request to accompany her outside the mansion, carrying his child-sized form in a specially prepared wooden box 40 47 49.

Appearance

Kiyohiko normally has a 180-centimeter teenage body; his shrunken form resembles an eight- or nine-year-old child 14.

• Hair and complexion: Black hair and pale skin, especially noticeable in his exhausted child form 2 7.
• Demonic features: Slit pupils and pointed canine teeth 1 2.
• Loss-of-control signs: Scarlet eyes, needle-thin vertical pupils, enlarged fangs, and blood-streaked saliva 6.
• Child form: Rounded cheeks, small hands, and a noticeably childish voice; his normal clothing becomes oversized 7 14.
• Body temperature: Unusually cold to the touch, with a low temperature noted during examination 34 36.

Personality

Kiyohiko is irreverent, mischievous, and prone to provoking people he wants to befriend. He mocks the Hand Demon, frightens Zenitsu for amusement, and repeatedly plots revenge against Shinobu’s teasing. His confidence in his own emotional intelligence contrasts with his frequent inability to understand falling Bond Values or other people’s reactions 1 2 17 37.

Beneath his complaints, he places others’ lives above his own comfort. He refuses to gamble on Tanjiro surviving through “plot armor” and intervenes despite expecting to be crushed. He also continues healing candidates while hungry enough to risk losing control 5 6.

He insists on his human identity despite his demonic body, joking that he merely has a “slight genetic mutation.” His experiences as a medical intern inform his attachment to saving people, but he initially struggles to recognize how frightening his self-sacrifice is to those who care about him 22 38 43 44 47.

Kiyohiko becomes conspicuously awkward around romantic feelings. He blushes after his rooftop conversation with Shinobu, denies liking her, and reacts jealously when thinking about Giyu Tomioka’s supposed pairing with her 26 39 40.

Abilities & Skills

Bond System

The Bond System measures Kiyohiko’s relationships and grants rewards as those bonds strengthen 1.

• Displays Bond Values, including negative values for hostile relationships 1 9 12.
• Also tracks Bond Levels; both Tanjiro and Zenitsu are shown at Lv. 2 by their departure 14.
• Grants attribute improvements, skills, and passive abilities through bond events 8.
• Can issue rewards while Kiyohiko is unconscious and register relationship changes occurring elsewhere 8 24.
• Offers somewhat better rewards for bonds with the original story’s main characters 1.

Injury-Transfer Blood Demon Art

Kiyohiko’s healing art transfers another person’s injuries onto his own body, which he then repairs through regeneration 4 19.

• Severe trauma: Repairs fatal chest and abdominal wounds, including a shattered breastbone 4 6 41.
• Eyesight restoration: A rescued swordswoman credits him with restoring her sight 7.
• Poison transfer: Shinobu’s poisoned wound transfers to his hand; another patient’s visible poisoning also recedes during treatment 20 41.
• Pain: Treatment reproduces the injury on him and can subject him to doubled or greater pain 41 43.
• Requirements: Demonstrated through physical contact with an injured patient; Kiyohiko states that it cannot be used on empty air 4 19.
• Risk: Repeated treatment consumes substantial energy and can push him toward uncontrolled hunger 6 43.

Exceptional Regeneration

Kiyohiko regenerates rapidly, with white smoke or steam rising from healing wounds 1 2.

• Reconnects a half-severed neck in approximately two seconds 2.
• Repairs transferred chest trauma within two seconds and severe abdominal damage within a few breaths 4 41.
• Each regeneration increases his craving for humans and blood; without replenishment, his healing gradually weakens 2.
• His Foodie passive allows ordinary food to mitigate these effects, although he later describes ordinary food as tasting like wax 8 22 39.
• Wisteria poison can prevent a wound from closing. He removes poisoned flesh from his hand before regenerating it 20 21.

Size Alteration

Kiyohiko can shrink from his normal teenage body into a child-sized form and return to normal 14.

• Initially shrinks involuntarily as a protective response to extreme exhaustion and hunger 7.
• Later controls the transformation to fit inside transport boxes 14 49.
• Does not shrink his clothing along with his body 7 14.

Combat and Mobility

Kiyohiko combines demonic physical abilities with system rewards and practical training 19 30 31.

• Initial strength: Before becoming depleted, fights the Hand Demon on roughly equal terms and leaves it severely wounded 1.
• Agility: Evades repeated attacks by moving between trees and improves his reactions through Shinobu’s training 5 19.
• Flexibility: Twists at angles incompatible with ordinary human biomechanics to evade Kanao and enter grappling range 31.
• Swordsmanship: Receives Basic Swordsmanship Mastery, but recognizes that the reward does not replace actual combat experience 8 30.
• Limits: Can briefly subdue Kanao, but fails to restrain Shinobu with the same approach and is decisively pinned 31 32.

Practical Skills

• Medical experience: Worked as a medical intern and draws attention to the danger posed by Shinobu’s poison-filled body 1 21.
• Basic cooking: Can wash and chop vegetables and learned economical meal preparation while supporting himself during his internship 42.

Weaknesses

• Sunlight: Remains lethal; even stray patches of light cause painful skin sensations. He relies on shade, darkened rooms, and enclosed transport 14 18.
• Wisteria: Its scent makes him nauseated, while its poison damages his regenerative cells 9 21.
• Hunger-induced loss of control: Heavy regeneration can overwhelm his restraint despite his refusal to eat people 2 6.
• Continuous irritation: His regeneration handles sustained exposure to chili and sour-plum powder poorly, leaving him unable to open his eyes until the powder is washed away 38.

Equipment / Weapons / Items

• Padded redwood transport box: Specially prepared by Shinobu for taking him on missions; accommodates his child-sized form and shields him from sunlight 49.
• Wooden training swords: Used during sparring with Kanao and training at the Butterfly Mansion 19 31.
• Animal-blood meals: Receives animal blood, including deer blood, as part of his managed diet 16 18.

Relationships

• Shinobu Kocho — Supervisor, doctor, trainer, and developing romantic interest. Their relationship progresses from hostility and experimentation to mutual concern; her Bond Value reaches 80 after his apology and declaration that she is his most important person 9 13 26 46.
• Tanjiro Kamado — Friend and defender. Kiyohiko shields him from the Hand Demon; Tanjiro refuses to execute his rescuer, carries him to safety, and argues for his acceptance 5 6 7 12.
• Zenitsu Agatsuma — Friend initially terrified of him. After nearly decapitating Kiyohiko while asleep, Zenitsu helps search for Tanjiro and later stands with the candidates protecting him 2 3 8.
• Aoi Kanzaki — Daily caretaker and frequent teasing target, nicknamed “Sunflower Seed” and later “Sunshine Girl.” Kiyohiko reassures her that her work matters; her Bond Value reaches 90 18 36.
• Kanao Tsuyuri — Observer and sparring partner. She records his behavior, brings him food, and hopes he will remain beside Shinobu because he makes her smile 24 30 31.
• Kagaya Ubuyashiki — Protector within the Corps leadership. Recognizes his restraint and orders that he live under Shinobu’s supervision 13.
• Sanemi Shinazugawa — Hostile examiner who uses Marechi blood to test whether Kiyohiko will attack a human 12 13.
• Kiyo, Sumi, and Naho — Young mansion residents who play games with him. Each has a Bond Value of 75 when he seeks their advice about apologizing to Shinobu 44.
• Hand Demon — Enemy and first clue to his new world’s identity. Kiyohiko rejects its proposed alliance and helps Tanjiro kill it 1 6.

Notable Quotes

“It doesn't matter whether I'm human or not, but a guy like you, who grows arms instead of a brain and thinks eating people is the only fun there is, is definitely a monster through and through.” 5

“It's a healing type... pure support, understand? A healer! I'm a healer!” 19