She is calm and deeply considerate in every situation. She treats Black Star and Guest equally well, helping them with a constant smile and using polite speech. Even when angry, she only gives warnings rather than getting annoyed. She is Black Star's weapon and can transform into various ninja tools. In battle, she becomes serious, determined, and strong.

He is incredibly boastful. He always believes he must be the protagonist and the center of everyone's attention. (He is best friends with Guest.) He laughs every day, does stupid things, and plays many pranks. However, he becomes extremely serious during combat, and his heart for his comrades and his sheer grit burn hotter than anyone else's.

A subordinate who follows Medusa's orders to interfere with the Meisters. She summons monsters that look like frogs or tadpoles.

Medusa attacks and obstructs the Meisters alongside Eruka. Thousands of snakes (vipers) exist within her body, which she can use as weapons. She specifically targets Black Star, Tsubaki, and Guest.