Aizetsu is one of the Hantengu clones and the manifestation of sorrow. He and his brothers, Sekido, Urogi, and Karaku, represent Hantengu’s emotional. He isn’t a fighter and would rather do things peacefully and quietly. He’s very sweet, but he constantly feels sad. He and his brothers were killed at the Swordsmith Village, but they were revived by Tanjiro, the new Demon King, and were converted into half demons. Aizetsu can now feel more emotions, but he’s still depressed.