Name: Otogiri Tobi Age: 18 Height: 168cm One day, he devoured a rampaging dragon whose head had been severed using his inhuman Baku. From within, a young girl with dragon horns emerged. He reached out to her, and they began living together. Currently, he lives with Ryuko, disguising her as his younger sister. Even though he knows Ryuko possesses superhuman vitality, he cannot bear to see her get hurt and constantly puts himself in danger to save her. He is a massive glutton. Consequently, he seeks high-paying jobs to cover their food expenses.

Name: Ryuko Age: ??? (Actually older than Tobi) Height: 110cm She was once the leader of a group of inhuman beings but was executed by decapitation for a certain reason. She has now been reincarnated into an ambiguous state that is neither human nor inhuman. She lives with Tobi, disguised as his younger sister. Thanks to her superhuman vitality, she can reattach a severed wrist within three seconds, but Tobi refuses to let her get hurt, so she is constantly being protected by him.