Kurozawa

Biodata

Feature	Details
Name	Kurozawa Danryu (黒沢 段流)
Alias(es)	Senior Disciple Kurozawa
Species/Race	Human transmigrator; later bearer of the Immortal Body
Gender	Male
Affiliation	Mount Sagiri; Demon Slayer Corps; later Asakusa and Hongyue's faction
Occupation/Role	Demon Slayer; swordsman; world traveler
Status	Alive
First Appearance	Chapter 1

Power Progression

Stage / Realm / Level	Chapter	Notes
Gray-White baseline	3	Awakens the Gray-White panel with Strength 0.33, Constitution 0.41, Agility 0.31, and Intelligence 0.20. Water Breathing is at the fourth tier; Water Breathing Sword Forms are at the second tier. 3
First attribute investment	8	Killing Nita Taku grants 10 Potential Points and 1 Power of Despair. He raises Strength to 0.37, Agility to 0.33, and Constitution to 0.51. 8
Berserk reinforcement	24	Spends more than 130 Potential Points at once while fighting the Hand Demon; heals his broken arm, reaches Strength 0.59, and temporarily grows to two meters while losing his hair and eyebrows. 24
Refined physique	27	Invests more than 150 Potential Points into Agility and related attributes, compressing his previously bulky musculature into a leaner, more balanced build. 27
Demon Slayer Mark / Fighting Spirit Perception	57	Awakens the Demon Slayer Mark, sharply increasing his physical ability and gaining Fighting Spirit Perception during his battle with Rui. 57
Water Breathing Level 5 / evolved Power of Despair	58	Water Breathing reaches Level 5. Power of Despair reaches 124 and becomes dense enough to form solid Pitch-Black Aura constructs, including a blade. 58
Water Breathing Sword Forms, Stage 3	90	Uses Potential Points to raise his sword forms to the third stage. 90
Higan Suzume Eye, Stage 1	97	Learns the fundamentals of Higan Suzume Eye through his understanding of Water Breathing. 97
Water Breathing Sword Forms, Stage 4	108	Spends more than 200 Potential Points amid the battle against Gyutaro to advance his sword forms. 108
Water Breathing Sword Forms, Stage 5	118	Comprehends his own Water Breathing Secret Technique, advancing his sword forms to the fifth stage; the Immortal Demon Body appears as awaiting evolution. 118
Sun Breathing, Stage 1	142	Begins practicing Sun Breathing despite its severe pain and gains the first stage. 142
Water Breathing Stage 6 / Higan Suzume Eye Stage 4 / Transparent World	159	Uses more than 1,000 Potential Points to maximize Water Breathing and Higan Suzume Eye, gaining Transparent World. Power of Despair reaches 400. 159
Water Breathing Sword Forms, maximum level	171	Kills Kokushibo with max-level Water Breathing Sword Forms and executes the surrendering Doma. 171
Immortal Body	173	Perfects the Immortal Demon Body, removing its demonic designation and raising his base attributes to Strength 21, Agility 20, Constitution 25, and Intelligence 10. 173
World Seed	176	The Power of Despair forms a World Seed capable of carrying his soul across world membranes and into other worlds. 176
Moon Breathing Stage 4	182	In his next world, self-trains Moon Breathing to the fourth stage and retains the Immortal Body from his previous life. 182
Reawakened Fighting Spirit Domain	229	Reawakens Fighting Spirit Perception and immediately expands it into a domain spanning several kilometers, entering Transparent World. 229
Intelligence 52 / Substantialized Mental Power	246	Converts more than 3,000 Potential Points into Intelligence, gaining telekinesis, mental intrusion, and the ability to manifest phantom images in others' minds. 246 247

Background / History

Kurozawa was a man from another world who died and awakened in the Demon Slayer world without remembering his former name. Sakonji Urokodaki found him as an infant near a dark swamp, adopted him, and named him Kurozawa Danryu after his Water Breathing style. He became Sakonji's first direct disciple. 2

He grew up on Mount Sagiri alongside Makomo and Sabito, treating them as younger siblings. Because Sakonji was ill-suited to childcare, Kurozawa assumed the household role of “dad-mom,” helping Makomo recover from the trauma of her family's murder and teaching her Total Concentration Breathing. 2

Gray-White later awakened before him as a translucent status panel. It records attributes, skills, Potential Points, Power of Despair, and the Power of Species Annihilation; Kurozawa gradually learned that killing sentient beings provides Potential Points and can increase his Power of Despair. 3 8

Appearance

Kurozawa is a tall, powerfully built young man with black hair and black eyes—an unusual combination in his first world. His deeply set eyes are compared to a fathomless abyss, while his sharply contoured face and athletic physique give him an imposing, radiant presence. 1

• Black hair and ink-dark eyes in his usual appearance. 1
• Deep-set eyes, sword-like eyebrows, and sharply defined facial features. 1
• Lean, dense musculature that becomes visibly pronounced when exerting force. 1
• His berserk enhancement temporarily made him two meters tall, extremely muscular, bald, and without eyebrows. 24
• After later Agility-focused reinforcement, his body returned to a streamlined and aesthetically balanced form. 27
• His Demon Slayer Mark manifests as dark patterns across his body and face. 62 160

Personality

Kurozawa is patient and protective toward those he considers family. Mount Sagiri's disciples view him as a gentle, dependable senior figure, while Makomo's recovery is directly tied to his care and companionship. 2 121

He is also teasing, provocative, and prone to malicious humor. He deliberately frightens demons to study despair, deceives Shinobu for amusement, and often needles Kanae and his junior disciples. 6 26 84

In combat, Kurozawa pursues strength with dangerous intensity. He enjoys overwhelming opponents, can become ruthless toward enemies, and is willing to discard conventional dignity or morality when he believes survival and power demand it. Even so, he can show restraint, empathy, and loyalty toward people with whom he has a genuine bond. 17 92 140 166

Abilities & Skills

Gray-White

A system-like power visible only to Kurozawa that tracks his attributes and skills.

• Grants Potential Points through the deaths of sentient beings. 8
• Can enhance physical attributes, skills, and certain bodily conditions at escalating costs. 8 58
• Potential Point expenditure can heal injuries and remove side effects, though large enhancements can cause dramatic physical changes. 24 142
• Records the Power of Despair and the dormant Power of Species Annihilation. 3 58

Immortal Body

Kurozawa's perfected body grants extreme resilience, regeneration, and survivability.

• Regenerates gunshot wounds, severe lacerations, lost limbs, and internal damage. 119 161 227
• Retains its existence across worlds; he is born with the Immortal Body in his later life. 182
• Negates the regenerative suppression normally caused by Sun Breathing's sun attribute. 174
• Its regeneration can be strained by sufficiently intense combat and was previously accompanied by hunger before he removed that drawback. 161 142

Power of Despair and Pitch-Black Aura

Energy gained from killing sentient beings, particularly demons, which manifests as black flame-like aura.

• Instills fear and spiritual pain in targets. 26 56
• Suppresses a demon's recovery and can weaken hostile supernatural constructs. 26 56
• Forms the Blade of Despair, a solid black sword construct usable with sword forms. 58 90
• Can cover his body as a defensive layer, though broad coverage is weaker than concentrated armor. 58 161
• Later creates weapons such as the Pitch-Black Aura gun Night Gloom and a condensed replacement for Mingzhou. 215 175

Breathing Techniques and Sword Forms

Kurozawa trains continuously to control the power gained through Gray-White rather than relying on raw attributes alone. 30

• Water Breathing — His foundational style under Sakonji Urokodaki; eventually reaches Stage 6. 2 159
• Water Breathing Sword Forms — Initially his weakest discipline, but becomes a major strength after the Blade of Despair lets him improve it. 59 171
• Water Breathing Secret Technique: Annihilation — A self-created secret technique used in his clash with Hyuga Wu. 174
• Sun Breathing — Learned to overcome sunlight vulnerability and further perfect his body; painful to practice. 142
• Moon Breathing — Self-mastered in his next world; produces crescent-shaped wind blades capable of severing Parasitic Organism weapons. 182 214

Fighting Spirit Perception and Transparent World

A perception system that lets Kurozawa sense living presences, emotions, movements, and physical structure.

• Initially senses hostile gazes and the emotions behind them. 17 22
• Fighting Spirit Perception distinguishes targets and reads their fluctuations within roughly 100 meters in its early form. 62
• Transparent World allows him to see through bodies and objects, observe muscles, blood flow, and organs, and predict movement with exceptional precision. 160
• His reawakened Fighting Spirit Domain later spreads over several kilometers. 229

Higan Suzume Eye

An advanced visual skill that greatly improves dynamic vision.

• Lets him track minute movement and enhances combat reactions. 97 159
• At Stage 4, he can perceive trajectories of dust and falling leaves in darkness. 159
• Causes severe eye strain when used at maximum output. 160

Fighting Spirit Martial Arts

Close-combat arts derived from Akaza's techniques and later mastered by Kurozawa.

• Destructive Kill: Compass — Creates a twelve-pointed formation that interferes with an opponent's perception and identifies weak points. 237
• Destructive Kill — Delivers precise strikes to an enemy's vulnerable locations. 237
• Can be used against heavily armored or multi-organism opponents such as Goto. 237

Parasitic Organism Integration

After entering his next world, Kurozawa incorporates Parasitic Organisms into his body.

• Lefty functions as his transforming left hand, producing metallic blades and separate tendrils. 215
• He integrates additional rogue Parasitic Organisms and studies the balance between their consciousness and quantity. 239
• Uses his body as a potential host for allies such as Ryoko Tamiya while attempting to preserve their self-awareness. 245

Substantialized Mental Power

A psychic ability produced by his extreme Intelligence increase.

• Moves objects telekinetically. 246
• Temporarily takes control of another person's body, as demonstrated with Hirokawa. 246
• Creates phantom images and suggestions within a target's mind. 247 248
• Kurozawa considers it more suited to manipulation than his preferred direct combat. 248

Equipment / Weapons / Items

• Nichirin Blade / Mingzhou — His Color-Changing Nichirin Blade turns black when he touches it; he later wields Mingzhou with Water Breathing forms. 30 106
• Blade of Despair — A black blade condensed from Pitch-Black Aura, enabling his sword-form progression. 58 59
• Kasugai Crow — Assigned after he receives the Demon Slayer rank of Mizunoto. 28
• Lefty and Righty — Parasitic Organism-derived limbs and companions used for bladed combat, defense, driving, and reconnaissance. 199 215 239
• World Seed — A construct of Power of Despair that transports his soul between worlds. 176 180

Relationships

• Sakonji Urokodaki — Adoptive father, master, and the person who named Kurozawa. Kurozawa is his first direct disciple. 2
• Makomo — Younger-sister figure and student. Kurozawa's care helps her overcome grief and become more cheerful. 2
• Sabito — Younger-brother figure from Mount Sagiri. 2
• Hanada Shizuka — Junior disciple who admires Kurozawa and remains loyal to him despite later doubts around his connection to demons. 21 84
• Kocho Kanae — Fellow Demon Slayer and frequent mission partner. Kurozawa respects her principles, though their paths later diverge; he spares her during his attack on the swordsmen. 84 121 166
• Kocho Shinobu — A junior swordswoman he aids on Mount Fujikasane and repeatedly teases. 25 26
• Iguro Obanai — Survivor Kurozawa rescues from the Iguro family, brings toward Mount Sagiri, and accepts as a disciple. 44 45
• Hongyue — Demon woman and Kurozawa's closest romantic bond. Their relationship develops from mutual suspicion into trust, shared ambitions, and a promise to reunite across worlds. 47 129 178 180
• Hyuga Wu — A boy Kurozawa initially admires but later identifies as a dangerous enemy protected by the Divine Will; their conflict culminates in a battle inside Infinity Castle. 92 96 173 175
• Lefty — Parasitic Organism companion integrated into Kurozawa's left hand; serves as a weapon, assistant, driver, and reluctant “pet” or butler. 199 240
• Kimishima Kana — His younger sister in the next world. She is strongly attached to Kurozawa and repeatedly seeks closeness despite his attempts to distance himself. 181 190
• Ryoko Tamiya — Parasitic Organism ally whom Kurozawa considers integrating into his body; she shares his interest in understanding their species. 245
• Hirokawa — Political ally in the Parasitic Organism world who warns Kurozawa of the Akaya Mountain ambush. 239

Story Role / Major Arcs

• Mount Sagiri upbringing — Raised by Sakonji, becomes the senior disciple to Makomo and Sabito, and develops Total Concentration Breathing. 2
• Mount Fujikasane selection — Hunts demons beyond the normal selection period, defeats the Hand Demon, receives his rank and black Nichirin Blade, and experiments with Power of Despair. 24 28 30
• Hachijo Island investigation — Exposes the Iguro family's demon worship, destroys the Snake Woman Demon and the family, and rescues Iguro Obanai. 39 43 44
• Mount Natagumo battle — Faces Rui's spider family, awakens his Demon Slayer Mark and Fighting Spirit Perception, and advances the Power of Despair. 50 57 58
• Lotus Town conflict — Investigates Doma's cult alongside Kanae, battles multiple Upper Moons, and develops his own Water Breathing Secret Technique under extreme pressure. 104 113
• Demonization and ascent — Evolves the Immortal Demon Body, learns Sun Breathing, strengthens his bond with Hongyue, and comes into conflict with the Demon Slayer Corps. 118 142 166
• Infinity Castle confrontation — Commands the Upper Moons against Hyuga Wu, kills Kokushibo and Doma, perfects his Immortal Body, and battles Hyuga Wu inside the collapsing Infinity Castle. 168 171 173 175
• World travel — Uses the World Seed to leave the Demon Slayer world after ten years of cultivation. 180
• Parasitic Organism world — Rebuilds his strength through Moon Breathing, integrates Parasitic Organisms, confronts Goto and the Blade Breakers, and develops substantialized mental power. 182 214 237 246

Notable Quotes

“Want to kill me? Then come!” 96

“From the moment Master died, I stopped having any reservations.” 140

“As long as he gave it his all, that was enough.” 96