Kaigaku

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Evil-doer
Full Name	Kaigaku
Alias	Upper Moon Six
Origin	Demon Slayer: Kimetsu no Yaiba
Occupation	Demon Slayer (formerly). Member of the Twelve Kizuki.
Powers / Skills	Enhanced Breath Techniques Breath of Thunder Style: Second Style: Lightning Ball Third Style: Buzzing Mosquito Thunder Fourth Style: Distant Thunder Fifth Style: Heat Lightning Sixth Style: Electric Lightning Shower
Hobby	Bullying.
Goals	Become the Thunder Hashira (abandoned).
Crimes	Attempted Murder Cannibalism Mass Murder
Type of Villain	Opportunistic Traitor

“	Get out of here... You gonna make me repeat myself?, leave my sight. You know why. The way you cry like a baby all day long. Aren't you ashamed of yourself?.. Good for nothing, any effort spent on you is an absolute waste of time. Our teacher is an extraordinary man. [..] Hey you, don't go being all familiar and calling him gramps! He's a former Hashira, someone who earned the highest tile in the Demon Slayer Corps. Hardly anyone ever gets the chance to be trained by a former Hashira. The time he spends training you is all for nothing its infuriating to see! I hate even looking at you so get out! Why are you even here? Why do you insist on clinging on like a patch of mold?!	„
	~ Kaigaku berating Zenitsu in the past.

Kaigaku (in Japanese: 獪岳，かいがく, Kaigaku) was a major antagonist in the 2016 horror fantasy manga and anime series Demon Slayer: Kimetsu no Yaiba.

Kaigaku was originally a Demon Slayer and member of the Demon Slayer Corps who aspired to become the Thunder Hashira, a title which had previously been bestowed on his master Jigoro Kuwajima. Kaigaku despised Zenitsu Agatsuma, Jigoro's cowardly second apprentice who he saw no promise in, often bullying the younger boy.

At some point Kaigaku was transformed into a demon by Kokushibou. He was quickly elevated to the position of Upper Moon Six of the Twelve Kizuki after the deaths of Daki and Gyuutarou. Kaiguku eventually met his demise at the hands of Zenitsu inside Kibutsuji's fortress.

He is voiced by Yoshimasa Hosoya in the Japanese version of the anime and by Alejandro Saab in the English version, the former of which has also voiced Wave from Akame Ga Kill! and Reiner Braun from Attack on Titan.

Personality

Although prodigetic, Kaigaku is an arrogant opportunitist who follows strong and despises the weakness, especially when it obstructs something he wants, as seen with his bullying words against Zenitsu.

Deep down, Kaigaku is also a coward, who cowered in fear at Kokushibou and knelt in front of him, willingly accepting Muzan Kibutsuji's blood and became a demon as a result. Kaigaku also shows no remorse for his own treachery and cowardice, even teasing his master, Jigoro Kuwajima, as a worthless weakling just like Zenitsu after discovering the latter committed suicide out of shame.

History

Early life

Kaigaku was an orphan and a thief, who had to eat scraps and steal to survive. This established a certain belief in his head, he started to believe that strength was the only thing worth respecting, and those who can‘t see true strength or are too weak aren’t worth respect.

Treachery

During his carrer as a Demon Slayer, Kaigaku was taken in by Jigoro Kuwajima, the Thunder Pillar. along with Zenitsu, and taught the Breath of Thunder style. Kaigaku became determined to become Jigoro Kuwajima’s successor and the new Thunder Pillar. However, Kuwajima revealed that Zenitsu would become his successor, since Zenitsu had potential to master the First Style in the Breath of Thunder, while Kaigaku had never mastered it even after mastering the other styles from the Second to the Sixth.

Believing he was losing his master's favor, Kaigaku began to despise Zenitsu for being merely a weak and timid man who earned his master's favor out of dumb luck. Thus, he started to bully Zenitsu constantly.

Later, Kaigaku went on a solo mission to hunt down Kokushibou, the Upper Moon One, but was overpowered. After the defeat, Kaigaku kneeled before Kokushibo and begged for his life. Kokushibo offered Muzan's blood to turn Kaigaku into a demon, which he accepted and became a man-eating savage. After finding out that his student betrayed him and renounced humanity, Kuwajima committed suicide out of shame.

Dimensional Infinite Fortress Arc

After the deaths of Daki and Gyutaro, Kaigaku was promoted to become Upper Moon Six of the Twelve Demon Moons and confronted Zenitsu as a rematch he always desired. Zenitsu informed his master's demise to his treachers classmate, accusing Kaigaku for the one to blame, but Kaigaku nonchalently disagreeded with him. He believed that those who praised him was good and those who don't was evil, and he didn't care about his master's death for ignoring him. Disgusted, Zenitsu called Kaigaku as a trash who can never master Breath of Thunder - First Style, and decided to part ways with his former prefect.

Since he was yet to master his Demon Skills fully, Kaigaku was ultimately beheaded by Zenitsu's Breath of Thunder Seventh Style: Flaming Thunder God. Kaigaku mockingly commented that their master do favor Zenitsu more for teaching him that style, until Zenitsu revealed that Flaming Thunder God was his own making, in order to fight alongside Kaigaku as equals, had him not turning into a Demon.

Hearing this, Kaigaku watched in shock and anger as Zenitsu was saved by Yushiro. Eventually, Kaigaku's head screams in anger as he disintegrated. Yushiro scornfully declared that Kaigaku will be given nothing since he never learned how to give, and Kaigaku's die-alone fate was sealed once he decided to let his desire inflate.

Gallery

Kaigaku (as a human) in the anime series

Kaigaku surrendered himself to Kokushibo

Kaigaku mocking his late master

Trivia

• It was widely speculated that Kaigaku was the very same treachous child in Chapter 135's flashback who betrayed Gyomei Himejima, who adopted him and eight other children, and lured a demon to his temple that killed other children out of fear of death, before framing Himejima for the murder.

Navigation

Villains

Demons Demon King Muzan Kibutsuji Twelve Demon Moons Original Upper Moons One: Kokushibou | Two: Doma | Three: Akaza | Four: Hantengu | Five: Gyokko | Six: Daki & Gyutaro Replacement Upper Moons Four: Nakime | Six: Kaigaku Lower Moons One: Enmu | Two: Rokuro | Three: Wakuraba | Four: Mukago | Five: Rui | Six: Kamanue Former Lower Moons One: Ubume | Two: Hairo | Six: Kyogai Muzan's Lesser Followers Snake Demon | Susamaru and Yahaba | Hand Demon | Swamp Demon | Spider Family (Father Spider | Mother Spider | Brother Spider | Sister Spider) Humans Tengan Uzui's Father | Gyutaro and Daki's Mother | Kyogo Shinazugawa | Iguro Family | Doma's Parents | Kanao Tsuyuri's Parents