Kaigaku, as a Demon-Slayer, could never master the basics of Thunder Breathing (First Form) and this might be why he could never surpass his senior. Moreover, Kaigaku met his end with a similar ...

Kaigaku is an important character in Demon Slayer, and you probably didn't even notice him. It will later transpire that he ...

Kaigaku was surprised by the new breathing form; however, he refused to accept his defeat, even in death. Demon Slayer Upper Moon Three Akaza was the first Upper-Rank demon to appear in the anime.