The highest-ranking Demon King in the underworld. High-tension and irresponsible. He looks like nothing more than a lazy flirt, but inside, he is cool, dry, and sharp-witted. With silky blonde hair and blue eyes, he looks like a sparkling prince. His magical power is outstanding. He has a fan club, likely because he's a feminist and soft on women. He is well-versed in Japanese trends.

A dignified demon and the Prime Minister. Tall and muscular, he's a power type. He seems to be constantly cleaning up the Demon King's messes, but in reality, he relies on the Demon King quite a bit. He has a wild personality and acts more like a king than the King himself. He has many secret fans of his stoic nature. He has reddish, curly black hair and dark gray eyes. He is straightforward and honest.

A demon who becomes Guest's attendant. Extremely silent. He usually speaks in single words, occasionally two. However, he's actually just shy. His inner thoughts are very noisy. A handsome man with glasses. A balanced type. He has black hair, red eyes, and a lean, muscular build. His almond-shaped eyes make his gaze look a bit sharp. He is always expressionless. He will follow almost any order.

A Japanese woman living in the underworld. She met the demon Garof on the surface, married him, and now lives underground. The couple gets along well. She gives advice to Guest. She has black hair, black eyes, and a small stature. Her catchphrase is "Momentum is everything!" and she has a bright personality. A bit airheaded. She occasionally returns to her parents' home on the surface and brings back souvenirs, but she prefers life in the underworld.

The one who kidnapped Guest to the underworld and Yuna's husband. A knight who has sworn loyalty to the Demon King. A balanced type. He is head over heels for his wife, Yuna, and is completely whipped, though he refuses to admit it. A hot-blooded, dog-like guy.