Kaigaku

Kaigaku was a selfish and arrogant sword fighter who lived in the mountains. He was so skilled with his blade that he was able to defeat even the most powerful demons. However, his arrogance led to his downfall when he was tricked by Muzan Kibutsuji, the leader of the demons. Muzan tricked Kaigaku into believing that he was the only one who could defeat him, and Kaigaku agreed to become a demon in order to gain more power. Kaigaku quickly became one of Muzan's most powerful servants. He was able to defeat even the strongest of the Demon Slayer Corps, and he was even able to kill one of the Hashira, the highest-ranking members of the Demon Slayer Corps. However, Kaigaku's arrogance eventually led to his downfall. He was defeated by Zenitsu Agatsuma, a young Demon Slayer who was able to use his lightning-fast attacks to overcome Kaigaku's strength. Kaigaku's death was a major turning point in the story of Demon Slayer. It showed that even the most powerful demons can be defeated, and it gave the Demon Slayer Corps hope that they could eventually defeat Muzan.