Zenitsu

Biodata

Feature	Details
Name	Zenitsu Agatsuma (善逸)
Alias(es)	Blondie 207
Gender	Male
Age	14 at introduction 145
Affiliation	Demon Slayer Corps
Occupation/Role	Demon Slayer; Thunder Breathing swordsman
First Appearance	Chapter 145

Power Progression

Stage / Realm / Level	Chapter	Notes
Thunder Breath: First Form — Thunderclap and Flash: Sixfold	166, 183	Repeated high-speed dashes; he uses the six-strike version to reach and decapitate Spider Father.
Total Concentration Breathing: Constant	171	Hiruma identifies this as a skill Zenitsu has achieved before the Final Selection's climactic challenge.
Thunder Breath: First Form — Thunderclap and Flash	173	While unconscious, Zenitsu unleashes a lightning-fast slash that curves around Genya and cuts through the Snow Demon's ice-spike body.
Thunderclap and Flash: Godspeed	184, 219	His fastest Thunderclap and Flash variation; it beheads Spider Father and later wounds Gyutaro and destroys his scythe. Its strain allows only one use per day.
Thunderclap and Flash — Eight Consecutive Strikes	216	Zenitsu consciously maintains an eight-strike assault against Daki, creating the opening for Inosuke to decapitate her.
Crimson Blade and Demon Slayer Mark	239	His golden Nichirin Blade turns crimson and lightning-like markings spread around his right eye when he protects Jigoro from Kaigaku.
Thunder Breath: Seventh Form — Fire Thunder God	248	Zenitsu's ultimate technique: a single, overwhelming lightning strike that decapitates Upper Rank Five Kaigaku.

Background

Zenitsu was abandoned by his parents at birth and survived alone on the streets for fourteen years. His fear of dying and desire to find a wife stem from this isolated upbringing. He used his extraordinary hearing to win Hanafuda games and secure money, though his infatuation with Tom led him into a demon's trap. 145

Kaigaku nearly killed Zenitsu while pursuing the demon that had cornered him, but Tendo Hiruma intervened and saved him. Hiruma later persuaded Zenitsu to learn swordsmanship by framing it as a way to become a heroic savior to women. 146 148

At Mount Peach, Jigoro Kuwajima accepted Zenitsu as a closed-door disciple of the Thunder Breathing lineage. Although frightened by the prospect of training, Zenitsu was deeply moved when Jigoro took him shopping and began treating him as family. 148

A lightning strike during his training turned Zenitsu's formerly black hair yellow. He struggled to learn forms beyond Thunderclap and Flash, but Jigoro urged him to perfect the single technique he possessed rather than abandon it. 157

Appearance

Zenitsu is a blond-haired young swordsman whose hair turned yellow after he was struck by lightning on Mount Peach. 157

• Golden eyes, particularly striking when he faces Kaigaku in Infinity Castle. 248
• Wields a golden Nichirin Blade that can become crimson. 239
• Wore a golden kimono while infiltrating the Flower District alongside Hiruma. 209

Personality

Zenitsu is intensely afraid of demons and death, frequently crying, fainting, or attempting to flee dangerous situations. His fear is closely tied to his lifelong loneliness and his conviction that he may die before finding a wife. 145 167

His cowardice contrasts sharply with his behavior in combat. When unconscious or fully resolved, Zenitsu becomes focused, composed, and exceptionally dangerous with a sword. He can also be confident and domineering when using his hearing advantage, as shown by his complete control of the Hanafuda table. 145 173

Despite his fear, Zenitsu is compassionate. He intervenes when Warabihime abuses a young girl, even after recognizing that the Oiran is a demon. His protectiveness toward Nezuko and loyalty to Jigoro ultimately motivate him to train seriously and confront Kaigaku. 211 219 239 241

Abilities & Skills

Extraordinary Hearing

Zenitsu possesses hearing precise enough to perceive details inaccessible to ordinary people.

• Detects cards concealed in sleeves and pockets during Hanafuda games. 145
• Can hear blood flow and distinguish breathing and heartbeats. 145
• May infer thoughts by listening closely enough. 145
• Detects threatening sounds, including the abnormal noise that warns the group something is wrong after Daki's decapitation. 216
• His instincts can be overridden by infatuation; he notices something suspicious about Tom but deliberately ignores the warning. 145

Thunder Breathing

Zenitsu specializes in Thunder Breathing, concentrating its speed and burst power into increasingly refined variations of Thunderclap and Flash.

• His unconscious state allows him to execute Thunder Breathing calmly and instinctively. 173 178
• Eight Consecutive Strikes can be performed while conscious, allowing him to coordinate with Inosuke against Daki. 216
• Godspeed is his strongest Thunderclap and Flash variation, but it heavily damages his legs and is limited to one use per day. 184 219
• Fire Thunder God is a Seventh Form capable of killing Kaigaku in a single strike, though it leaves Zenitsu's calves bleeding from the recoil. 248

Demon Slayer Mark and Crimson Blade

Zenitsu activates both the Demon Slayer Mark and a Crimson Blade while defending Jigoro from Kaigaku.

• His Nichirin Blade turns crimson. 239
• Golden lightning-like markings rise along his neck, circle his right eye, and settle on his forehead. 239
• The transformation is driven by his determination to protect the family that took him in. 239

Equipment

• Golden Nichirin Blade — His primary weapon; it becomes a Crimson Blade during his battle with Kaigaku. 239
• Chutaro — His sparrow messenger, which accompanies him on missions. 176
• Save Your Life Three Thousand — Healing medicine used after the lightning strike and again after Fire Thunder God's recoil. 157 248

Relationships

• Jigoro Kuwajima — Master and chosen grandfather. Jigoro accepts Zenitsu as his closed-door disciple and urges him to master his one known form; Zenitsu later risks his life to protect him from Kaigaku. 148 157 239
• Tendo Hiruma — Senior disciple and benefactor. Hiruma saves Zenitsu from Kaigaku's reckless attack, brings him to Mount Peach, and becomes part of the family Zenitsu vows to protect. 146 148 239
• Kaigaku — Enemy within the Thunder Breathing lineage. Kaigaku disregards Zenitsu's life, attacks Jigoro, and is ultimately killed by Zenitsu's Fire Thunder God. 146 239 248
• Tanjiro Kamado — Teammate and friend. Tanjiro repeatedly protects and encourages Zenitsu, while Zenitsu fights to protect Tanjiro's sister. 168 180 219
• Nezuko Kamado — Zenitsu is immediately infatuated with her after meeting her and becomes fiercely protective of her. They share an affectionate dream of picking peaches together. 179 195
• Inosuke Hashibira — Frequent rival and fellow member of the trio. Their arguments and competition often disrupt training, but they coordinate effectively against Daki and Gyutaro. 176 216 241

Story Role / Major Arcs

Recruitment and Thunder Breathing Training

• Survives alone as an orphan by exploiting his extraordinary hearing in Hanafuda halls. 145
• Is deceived by Tom, cornered by a demon, and saved from Kaigaku's indiscriminate attack by Hiruma. 146
• Becomes Jigoro Kuwajima's closed-door disciple on Mount Peach. 148
• Is struck by lightning, turning his hair blond during training. 157

Final Selection

• Enters Final Selection only after Jigoro forces him to confront his fear. 167
• Is repeatedly protected by Tanjiro, Genya, and Inosuke during the selection, but reveals his Thunder Breathing against the Snow Demon. 168 173
• Demonstrates Total Concentration Breathing: Constant before Hiruma's challenge against the Snow Demon. 171

Early Demon Slayer Missions

• Defeats the Long-Tongued Demon while unconscious after Hiruma throws him into the Demon's Home. 178
• Falls in love with Nezuko upon discovering her in Tanjiro's box. 179
• Enters Mount Natada despite his fear because he refuses to leave Nezuko in danger. 180
• Uses Six Consecutive Thunderclap and Flash to defeat Spider Father, then uses Godspeed to behead the demon threatening Nezuko. 183 184

Entertainment District

• Infiltrates Kyogoku House disguised as a woman alongside Hiruma. 209 210
• Protects a young girl from Warabihime and is captured beneath the Flower District. 211
• Works with Inosuke to decapitate Daki, then endures Gyutaro's assault using Eight Consecutive Strikes. 216
• Uses Godspeed to save Nezuko, wound Gyutaro, and destroy his scythe. 219

Kaigaku and Infinity Castle

• Defends Jigoro from Kaigaku, awakening his Mark and Crimson Blade. Hiruma's arrival ends the immediate assault, but Kaigaku later confronts Zenitsu again in Infinity Castle. 239 248
• Trains with renewed determination to avenge Jigoro and protect Nezuko. 241
• Enters Infinity Castle specifically to kill Kaigaku. 247
• Uses Fire Thunder God to decapitate Kaigaku in one strike, avenging his grandfather and ending Upper Rank Five. 248
• Is counted among the fighters whose final collective strike represents sincerity. 260

Notable Quotes

“Stay away from Grandpa, you bastard!” 238

“Bastard, I'm going to kill you!” 239

“You're nothing special!” 248

Trivia

• Zenitsu's messenger is a sparrow, Chutaro, rather than a Kasugai Crow. 176
• He was undefeated at Hanafuda from the age of eight due to his hearing. 145
• His hair changed from black to yellow after being struck by lightning. 157
• His strongest techniques place severe strain on his legs. 219 248