Male. The master of the Demon Castle and the Demon King. He's quite a klutz, and watching him makes you wonder, "Is this guy really the Demon King?" He has a human form with green hair and horns on both sides. He's about 60 years old, but looks around 20. In truth, he doesn't want war and aims to live peacefully. He occasionally tries to maintain his dignity. Uses informal speech.

Male. Real name is Leonard. He handles the resurrections of demons and the princess in the Demon Castle. He has a handsome human-like face and goat-like horns. He has a one-sided crush on the princess and is quite obsessed with her. Usually calm and gentle, but he makes a huge fuss whenever the princess is involved. Despite his appearance, he is a Great Demon who has lived for centuries. Uses polite speech. One of the Ten Elders.

Male. The Demon King's loyal hound who values discipline and demands the princess act like a proper hostage. He has served the Demon King for a long time, leading many Red Siberians to maintain public order in the castle. A rigid man with no particular hobbies or preferences and zero flexibility. His speech ends in a blunt, formal tone. One of the Ten Elders.

Male. A divine monster. Hades' younger brother and god of the sea, but was reincarnated as a demon. He looks like a boy, but in terms of physical age, he's just slightly younger than the Demon King. He doesn't wear a shirt. He complains a lot but is childish and likes cute things. Uses informal speech with everyone. One of the Ten Elders.

Male. A divine monster. He calls Tasogare a "brat," but he's actually only slightly older. Poseidon's older brother. One of the Ten Elders.

Male. While he contributes by creating numerous mechanical devices, he is a major headache. A total shut-in. One of the Ten Elders.

Male. Attacks primarily with fire and poison. Since he carries potent poison in his mouth, he wears a face shield to prevent accidents. One of the Ten Elders.

Male. He takes the form of a gentle, handsome young man but is hot-tempered. He was defeated by the Hero, and his magical powers were subsequently sealed. One of the Ten Elders.

Female. A silkmoth demon. She was close to the princess's grandmother, which became a trauma; now she collapses whenever she sees the princess, who resembles her. One of the Ten Elders.

Female. A plant-type monster. Her status-effect attacks and charm are lethal. She fundamentally believes in the inherent goodness of people. One of the Ten Elders.