The protagonist. A second-year middle school boy in class 2-1. He has short black hair. Having lost his mother in a murder case, he lives with his grandmother while striving to perform the good deeds his mother taught him. He was bullied by Sekiya and other classmates for trying to stop their harassment, but after receiving the "Key to Open the Gates of Hell" from an old man at a hellish roadside stall, he sent Sekiya and the others to hell. Now, he throws himself into various battles to punish the villains in town. His power increases each time he uses the key, but a bruise-like mark is appearing on his right wrist; he will likely be sent to hell himself if he overuses it. He speaks with a gentle tone but has no light in his eyes. Even when beaten, he doesn't glare at others, only showing pain.

A middle school boy in class 2-3 and Asura's classmate. He has short, dyed hair. He became friends with Asura after stopping other students from bullying him. He witnessed Asura using the key to open the gates of hell. Like Asura's mother, he seems to have trauma related to his father. He speaks like a delinquent but is kind-hearted, though he is quick to use his fists and is an incredibly strong fighter.