Demon Slayer: Is Kaigaku an Upper Moon? Explained

Taking a look at Kaigaku
Taking a look at Kaigaku's backstory before he became an Upper Moon 6 demon (image via Koyoharu Gotouge/Shueisha)

Demon Slayer’s Swordsmith Village arc is well underway, and the series is inching closer toward some of the most important and interesting story arcs explored in the manga. Most anime-only fans of the series might not be aware of this name, but Kaigaku was a character that made an appearance in the Infinity Castle arc.

This story arc is arguably one of the most anticipated story arcs since it involves some of the toughest demons that this series has. Additionally, vfans will also get to see other Hashiras in action and display their true strength.

As for Kaigaku, he was a demon, but fans often wonder whether or not he was an Upper Moon demon. To answer that question, Kaigaku was an Upper Moon 6 demon who replaced Daki and Gyutaro’s after they died.

Disclaimer: This article contains massive spoilers from the Demon Slayer manga chapters.


Who is Kaigaku, and what was he known for in the Demon Slayer manga?

If one recalls Gyomei Himejima's backstory in the Demon Slayer series, there was a child who had stepped out of the temple’s boundaries at night, despite being advised not to. Here, a kid let a demon trick him, and he ended up putting off all the Wisteria incense that kept the demons at bay.

This led to the demon entering the temple’s premises and killing the orphan children that were present there. Gyomei was forced to use his brute strength and beat up the demon until sunrise to kill it. However, the kid that triggered this entire chain of events was none other than Kaigaku.

Kaigaku was also a student in the same dojo where Zenitsu Agatsuma trained. He trained under Jigoro Kuwajima, the former Thunder Hashira and Zenitsu’s teacher. Kaiagaku was the type of person who would do anything to survive and had no honor.

One day, he came across Kokushibo, the Upper Moon One demon. Naturally, Kaigaku was no match for him and he was forced to yield, but Kokushibo offered him some of Muzan’s blood, extending the offer for him to live life as a demon. Kaigaku immediately agreed and became a demon.

Following this, Jigoro was forced to commit seppuku (ritual suicide) since one of his students turned into a demon. In the Demon Slayer series, viewers have already seen Zenitsu’s fond relationship with his teacher. Despite being a coward, he continued to train because his teacher believed in him. Zenitsu truly cherished Jigoro as a person. However, he was enraged when he found out the real reason behind his teacher's death and wanted to avenge him. During the Infinity Castle arc, Zenitsu finally met Kaigaku and fought against him.

This is arguably one of the most hyped fights in the Demon Slayer series for two reasons. First, Zenitsu fought this demon while being completely conscious the entire time. He didn’t faint from fear and let his instincts take over. Secondly, Zenitsu talked back to Kaigaku and verbally assaulted him before engaging in a fight. Kaigaku was ultimately defeated by Zenitsu, who had created a new technique in Thunder Breathing to finish the demon.

Kaigaku was a despicable character who is unanimously hated by the entire Demon Slayer fanbase for the things he had done. This is the story of Kaigaku, who was once a swordsman but turned into a demon out of fear and desperation to live.


Stay tuned for more Demon Slayer anime and manga news as 2023 progresses.

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