He is Hotaru Haganezuka. He takes care of Kotetsu, a kid who owns a battle doll. He is 37 years old, he lives in the Swordsmith Village, he's a Swordsmith. His favorite food is Mitarashi Dango. He hates the name "Hotaru" because it sounds cute, and hates the village chief because he's the one who named him that. The name of the village chief is Tecchin Tecchikawahara. He is very impatient and stubborn, he has a love-hate relationship with Tanjiro.