Hotaru Haganezuka

A swordsmith of the Demon Slayer Corps. A man with a hyottoko mask and several wind chimes hanging from his hat. Although his face is rugged and well-formed, his personality, as mentioned later, has led him to remain single at 37 years old. He is self-centered and has a very irritable nature, not listening to others and talking unilaterally. He has a strong affection for the swords he forges, and chases Tanjirou with a blade every time Tanjirou damages his sword in fierce battles. His skills are solid, but these personality traits often lead to him being disliked by swordsmen and frequently removed from assignments.

His favorite food is mitarashi dango, and offering it to him calms his mood, and tickling him under the arms makes him docile.

From a young age, his quirks were so strong that they caused his parents to become neurotic, and he was left in the care of Tetsutane, who raised him. His name, Hotaru, was given by Tetsutane, and he laments that it is "too cute."

Later, in the Swordsmith Village arc, he holds a grudge due to the aforementioned events, and instead of forging a new sword for Tanjirou, who had lost consciousness during a battle in the entertainment district, he sends a cursed letter. When Tanjirou visits the village to negotiate directly, Hotaru throws a tantrum and goes missing. However, after hearing from Muichiro the importance of swordsmiths as explained by Tanjirou, he reconsiders his thoughts. Even in a war-like situation and despite being injured, he concentrates his mind and body to the extent that he is undisturbed while re-sharpening a sword stored in the Yoriichi Zero model.