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It has been disclosed in the manga that Zenitsu’s “grandpa”, Jigoro Kuwajima, has passed away. He reportedly suffered a painful death.
Jigoro was a former thunder Hashira and acted as a grandfather figure to Zenitsu. He was the only source of guidance and support for Zenitsu, as Zenitsu did not have parents growing up.
Jigoro recognized the potential in Zenitsu and rescued him from a pile of debt after he was swindled by a young woman. He trained Zenitsu to be a demon slayer, constantly pushing him to be his best and providing encouragement along the way.
Jigoro was the first person to have faith in Zenitsu which motivated him to become a demon slayer, even though he never initially wanted to pursue this path. Despite Zenitsu’s tendency to flee in fear, Jigoro never gave up on training him. This made Jigoro someone that Zenitsu deeply loved and appreciated, because as for Zenitsu, Jigoro is the only one who never abandoned him.
His well-known quote is:
“It’s all right to cry. It’s alright to run away! But don’t ever give up! Believe in yourself. Become the strongest blade of all!“Jigoro Kuwajima from Demon Slayer: Kimetsu no Yaiba
These words have become ingrained in Zenitsu’s personality, causing him to be determined and is not easily discouraged.
In addition to Zenitsu, Jigoro also trained another student named Kaigaku.
Who Is Kaigaku?
Kaigaku made his first appearance in episode 17 of season 1. During their training together, Kaigaku would often bully and belittle Zenitsu, calling him a crybaby and a waste of Jigoro’s time. This likely contributed to Zenitsu’s low self-esteem and lack of confidence in himself.
Kaigaku was able to use all forms of thunder breathing except the first, which is the most crucial and foundational form. Because of this, other demon slayers would mock him and predict his death.
Despite Kaigaku’s mistreatment of Zenitsu, he stood by his side, defending him from the other demon slayers who talked behind his back. Zenitsu even wrote letters to Kaigaku but never received a reply.
Kokushibo, the strongest among the upper moon demons, were among the few people whom Kaigaku respected. In chapter 145 of the manga, Kaigaku realizes that he is not strong enough to defeat Kokushibo and surrenders by kneeling down with his sword below his head. Kokushibo saw potential in Kaigaku, perhaps due to their shared background as former demon slayers and a desire to live longer. As a result, Kokushibo gave Kaigaku blood from Muzan‘s cells, turning him into a powerful demon.
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How Did Jigoro Kuwajima Die?
During the Hashira Training Arc, the revelation surfaces that Kaigaku had turned into a demon. Jigoro, ashamed of having raised a failed user of the thunder breathing style, committed seppuku, a form of ritual suicide by disembowelment that was traditionally practiced by Japanese warriors to restore honor.
Chuntaro informs Zenitsu of Jigoro’s death, causing Zenitsu to break down in tears and scream. He describes that Jigoro had to endure the pain until his death alone.
Kaigaku vs. Zenitsu
In the Infinity Castle Arc, Zenitsu and Kaigaku reunite for the first time since they left their master Jigoro. Kaigaku continues to insult Zenitsu, calling him weak and shabby. He shows no remorse for Jigoro’s death and even goes as far as to curse him for his foolish actions and wishes death upon Zenitsu. He states that individuals who don’t appreciate him are not significant. This is because he had hoped to become the sole heir to the thunder-breathing style, but Jigoro refused. Thus, Kaigaku harbors intense anger towards Jigoro for this.
Kaigaku and Zenitsu then engage in a heated battle, with Kaigaku using a combination of five breathing techniques plus his blood demon art to enhance his thunder forms. Zenitsu realizes that Kaigaku has likely consumed many people for him to grow this strong. Zenitsu argues that Kaigaku has lost his sense of morality, but Kaigaku responds that the only thing that matters is being acknowledged and recognized and that only those who value him are considered good.
Because of this, Zenitsu uses his ultimate move, “Thunder Breathing, Seventh Form: Honoikazuchi no Kami” (the god of fire-causing thunder), and cuts through Kaigaku’s neck in one swift motion. Kaigaku accused Jigoro of favoring Zenitsu because of the seventh breathing style; Zenitsu asserts that the technique was his own creation and that Jigoro treated both of them equally.
Yushiro arrives and informs Kaigaku that there is more to life than just seeking validation from others as Kaigaku’s body disintegrates. As Kaigaku never showed kindness, he must die alone with no one to grieve his passing.
Zenitsu and Jigoro have a brief reunion in the afterlife, where Zenitsu apologizes for not being able to have a better relationship with Kaigaku. In which Jigoro proudly states that Zenitsu was his greatest accomplishment with tears of joy on his face. One of the most touching panel in Demon Slayer.
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