Kaigaku is the Upper Moon Rank Six in Demon Slayer: Kimetsu No Yaiba. He is one of the main characters and villains in Infinity Castle Arc in Demon Slayer Series. Kaigaku replaces Daki and Gyutaro after they die fighting Tanjiro and Tengen.


No. Kaigaku and Zenitsu are not related by blood or are siblings. It is often confusing as they both use the Thunder Breathing Style. But this is only due to the fact that Jigoro, the former thunder hashira, trained both of them. Kaigaku is Zenitsu’s senior in the training grounds.

Along with that, they share a deadly rivalry that later turns into one of the most intense battles in Demon Slayer.

Who’s Kaigaku Rival?

Zenitsu is the primary rival of Kaigaku. He is the nemesis of Kaigaku. Their rivalry started when Jigoro, the former thunder hashira, took Kaigaku and Zenitsu both under his wing and started teaching them swordsmanship. Kaigaku decided that he would succeed the thunder hashira.

Kaigaku vs Zenitsu | by Gabriela Pifano
Kaigaku vs Zenitsu | by Gabriela Pifano

Who Defeated Kaigaku?

Zenitsu Agatsuma defeated Kaigaku in the Infinity Castle Arc. They both fight as if they don’t care about their life. Kaigaku used his enhanced blood demon art combined with his thunder breathing style. Zenitsu, on the other hand, used the Thunder Breathing Style.

Kaigaku ate many humans after becoming a demon, which boosted his strength drastically. But, Zenitsu defeated Kaigaku using his own created thunder-breathing form – Thunder Breathing, Seventh Form: Honoikazuchi no Kami.

Who is stronger, Daki or Kaigaku?

Kaigaku is definitely stronger than Daki. Kaigaku, before becoming a demon, was a demon slayer who used Thunder Breathing Style. It is said that turning someone who is skilled in Breathing style into a demon is hard. They require a lot of Muzan’s blood.

Just this fact that Kaigaku took a ton of Muzan’s blood is enough to say that he was stronger than Daki. Along with that, he could use both Blood Demon Art and enhanced Thunder Breathing Style when he became a demon.

Later, it was even said that Kaigaku would climb ranks very quickly and easily if he continued to eat humans for a year or two, which was very less in terms of Demon years.

Daki Demon Slayer

What Moon Rank Is Kaigaku?

Kaigaku is the Upper Moon Rank Six. He takes this position after Daki and Gyutaro die in the Entertainment District Arc. Kaigaku is the second person who became a demon after learning the breathing style. He ate a lot of humans to become stronger quickly.

What Episode Does Kaigaku Appear In Demon Slayer?

Kaigaku appears in Episode 17 of the anime in Demon Slayer: Kimetsu no Yaiba. He is seen as the student of Jigoro, the former Thunder Hashira and comes in Zenitsu’s flashbacks. Zenitsu was fighting a strong spider demon when he remembered Kaigaku.

What Manga Chapter Does Kaigaku Appear In Demon Slayer?

Kaigaku first appears in Chapter 34 of the Demon Slayer Manga. Zenitsu remembers him when he is fighting a demon from the spider demon family. Later, in the Infinity Castle Arc, Kaigaku appears in his Demon Form. He is first shown in real in Chapter 143 of the manga.

How Strong was Kaigaku?

Kaigaku was a strong demon slayer even before he became a demon. He took an abundance of Muzan’s blood to convert himself into a demon. Even after that, he was able to survive the effects of Muzan’s blood and become a demon.

After becoming a demon, Kaigaku could use Blood Demon Art and an enhanced version of Thunder Breathing Style, including black thunder. He became very strong after becoming a demon. After eating a ton of humans, he became the Upper Moon Rank Six.

It was even said that he would climb even more ranks if he got a year or two to get stronger. Unfortunately for him, our heroes get into Infinity Castle to fight him before he turns into an absolute monster.

Is Zenitsu Stronger than Kaigaku?

Yes. At first glance, Kaigaku seems much stronger than Zenitsu. He has a blood demon art and a thunder-breathing style. He can control black lightning and generate them from his flesh and blood. But during the fight in Infinity Castle Arc, we see that Zenitsu pushed his limits and defeated Kaigaku.

He also was on the verge of dying but could defeat Kaigaku by creating his own form – Thunder Breathing, Seventh Form: Honoikazuchi no Kami.

Kaigaku Backstory with Zenitsu by animefan0526
Kaigaku with Zenitsu by animefan0526

Who Turned Kaigaku into a Demon?

Kokushibo turned him into a demon. During the Hashira Training Arc, Kaigaku had terrible luck in meeting Kokushibo. And, when he saw how powerful the Upper Rank was, he knelt down and gave up to save himself.

Kaigaku becoming a demon after taking Muzan's blood
Kaigaku becoming a demon after taking Muzan’s blood | from Wiki

Is Kaigaku Zenitsu’s Brother / Are Kaigaku and Zenitsu Siblings?

No. Kaigaku and Zenitsu aren’t related by blood. Kaigaku is only Zenitsu’s senior. They both trained under the former Thunder Hashira, Jigoro.

Who Is Stronger Kaigaku or Gyutaro?

Kaigaku is stronger than Gyutaro, for sure. Kaigaku used the Thunder Breathing Style before he turned into a demon. People say that it is hard to turn someone skilled in the Breathing style into a demon. They need a lot of blood from Muzan.

Just the fact that Kaigaku took a lot of Muzan’s blood shows that he was stronger than Gyutaro. Also, when he turned into a demon, he could use both Blood Demon Art and an improved version of Thunder Breathing Style.

Later, it was said that Kaigaku would quickly and easily move up the ranks if he ate humans for a year or two, which was a short time in Demon years.

Kaigaku Backstory by Dayamations
Kaigaku by Dayamations

Why did Kaigaku turn into a demon?

During the Hashira Training Arc, Kaigaku met Kokushibo. And, when he saw how powerful Kokushibo was, he knelt down and gave up to save himself. He begged for his life and agreed to become a demon. Kaigaku was often the person who could do anything to save himself.

Is Kaigaku an Upper Rank?

Yes, after becoming a demon, Kaigaku ate humans here and there to gain strength. He quickly became the Upper Rank Six replacing Daki and Gyutaro after they died.

Why does Kaigaku hate Zenitsu?

Kaigaku had a terrible backstory and brutal childhood. He knew that to survive, he had to gain tremendous strength. He hated Zenitsu because of Zenitsu’s timidness and lack of strength. He often got irritated when Jigoro said that they both would inherit as Thunder Hashira.

Kaigaku thought that Zenitsu wasn’t strong enough and didn’t even know the later forms of the Thunder Breathing Style. He considered himself to be stronger and suitable to become the Thunder Hashira.

Kaigaku Backstory | by Chizzusan
Kaigaku | by Chizzusan

How Old is Kaigaku?

Kaigaku is slightly older than Zenitsu. He is about 19 years old.

In what Chapter does Zenitsu fight Kaigaku?

Chapters: 143-146

Zenitsu fights Kaigaku throughout chapters 143 to 146. The fight goes on for four chapters and features a ton of action and climaxes. Kaigaku first appears as a Demon in Chapter 143 in Infinity Castle Arc. Soon after, the two breathing-style users start fighting.

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Logan Rane

Hey, I'm Logan, and I love anime and manga. I could talk about them all day, write about them non-stop, and watch them around the clock. I've watched hundreds of animes and read thousands of mangas at this point in my life - so you could say I'm pretty deep into it all.

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