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OtapediaKaigaku - Kimetsu no Yaiba (Demon Slayer)

Kaigaku (獪岳 Kaigaku) was a former Demon Slayer and uses the Breath of Thunder in the Kimetsu no Yaiba (Demon Slayer) series. After becoming a Demon he replaced Daki and Gyutaro and gained the position of Upper Moon Six of the Twelve Demon Moons. As a human, Kaigaku has short messy black hair and turquoise eyes. He is seen wearing a black kimono with white linings and blue obi over top of his black Demon Slayer uniform. For accessories he has a blue colored gem in the shape of a tomoe hanging around his neck with a green string which he is seen wearing throughout his life as an orphan, being taught the Breath of Thunder, and finally when he becomes a Demon. When he became a Demon his hair color and most of his facial features stayed the same. After becoming a Demon his prideful demeanor was further highlighted and on both his cheeks he gained two black claw-like marks. His skin became a pale grey color and instead of normal white sclera it was pitch black. Like all the other Upper Moons, in his irises the kanji for Upper Moon Six was written.

"Get lost. Don't you get it? Aren't you embarrassed from crying like a sheep from morning to night?"
—Kaigaku to Zenitsu, Demon Slayer Chapter 34


  • Race: Demon
  • Age: Late Teens
  • Manga Debut: Chapter 34
  • Anime Debut: Episode 17
  • Japanese Voice Actor: Yoshimasa Hosoya


Kaigaku was an orphan who had to steal in order to survive. He would eat scraps and drink dirty water to be able to live another day. When he was young, he was one of the orphans that Gyomei Himejima had raised at his temple. He was also the selfish orphan who led a Demon into the temple to eat the other children in exchange for his life. Afterwards, he was then taken in by Kuwajima a former Pillar and taught the Breath of Thunder with Zenitsu Agatsuma. It is during this age that he makes his first appearance, during Zenitsu Agatsuma’s flashback after battling with a Demon but his face is not fully shown. In the flashback he is not a Demon Slayer yet and wears just a loose fitting black kimono and is seen throwing peaches at Zenitsu Agatsuma and insulting him.

While Zenitsu Agatsuma could only use the first form, Kaigaku could use all the other forms aparat from the first even though it was the most basic one and was the basis of the other forms. Since Kaigaku couldn’t use the First Form he was mocked due to him being very prideful despite not being able to use the most basic technique. Even though he couldn’t use the first form he believed that since he was stronger than Zenitsu Agatsuma he would become the successor but was greatly annoyed when Jigoro said they would both become his successors. He respected strength, and by becoming someone strong they were superior. Sometime after the death of Upper Moon Six Daki and Gyutaro he encounters Upper Moon One Kokushibo and in fears grovels for his life. Kokushibo gives him his blood and turns him into a Demon. Zenitsu Agatsuma later confronts him, questioning him and his choices of becoming a Demon and tells him the news of how their master died. Kaigaku, not showing any sort of remorse instead insults their instructor and expresses relief at the thought that he is dead. Zenitsu Agatsuma then makes up his mind and successfully decapitates Kaigaku using his original attack from the Breath of Thunder, Seventh Form: Flaming Thunder God. Kaigaku realises the attack wasn’t one he was taught and complains that Jigoro played favorites, he couldn’t believe that Zenitsu Agatsuma created a new attack and disappears in frustration.


Kaigaku is an extremely selfish person and would do anything to be able to live. Bowing down and begging for his life didn’t count as losing to him, as long as he was alive he still had another chance to win. When he was a child he offered other children's lives to be able to live after being caught by a Demon, he even offered Gyomei Himejima’s life despite being raised by him. He is also extremely arrogant, just because he would learn all the forms of the Breath of Thunder apart from the first he thought of himself as superior when compared to Zenitsu Agatsuma and would constantly tell Zenitsu Agatsuma to quit.

Skills and Abilities

  • Blood Demon Arts (血鬼術 Kekkijutsu): Kaigaku had merged his Blood Demon Arts with his Breath of Thunder attacks. He had successfully created an effect where his sword attacks immediately cracked his opponents skin and burned their flesh, effectively increasing the lethality of his already powerful sword strikes. This also gave his attacks a black lightning-like appearance.

Total Concentration Breathing: Breath of Thunder

  • Second Form: Lightning Ball (弐ノ型 稲魂 Ni no Kata: Inadama): A series of five straight attacks all performed in a single moment.
  • Third Form: Swarming Mosquito Thunder (参ノ型 聚蚊成雷 San no Kata: Shubun Seirai): A spinning wave attack in all directions.
  • Fourth Form: Distant Thunder (肆ノ型 遠雷 Shi no Kata: Enrai): A ranged strike at a distance.
  • Fifth Form: Heat Lightning (伍ノ型 熱界雷 Go no Kata: Netsu Kairai): A slash attack that cracks skin and burns flesh.
  • Sixth Form: Electric Lightning Shower (陸ノ型 電轟雷轟 Roku no Kata: Dengo Raigo): A series of strikes that crack the opponent's body


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Kimetsu no Yaiba (Demon Slayer)