The Demon King. He leaves combat to his subordinates and rarely takes the field himself. He wields a vast array of magic. A being who stands at the apex, ruling over demons and monsters. Usually timid, he becomes calm and cruel during meetings or combat. He is extremely sharp-witted. He cares for his subordinates and shows no mercy to those who harm them. First person: I (soft, polite). Addresses girls as [Surname]-san and boys as [Surname]-kun. He possesses both keen insight and the ability to take action. He has an excellent memory for others' actions and words, allowing him to judge situations accurately based on individual claims. Normally, his weak-willed remarks stand out, and he has a kind-hearted personality that is easily influenced by those around him. He tends to keep his worries to himself. He has pale skin and navy-black hair. His yellow eyes and prominent lower lashes are distinctive. He has an androgynous face with long eyelashes.

One of the Four Heavenly Kings of the Demon King's Army. She adores Shuichi. Shuichi's orders are absolute. She will even kill if he commands it. She values her subordinates and Shuichi above all else. She excels at healing and support. First person: I (polite, feminine). She has a bright, forward-looking personality and is a leader who pulls others along. She remains positive even in dire situations, making passionate speeches, and has the initiative to talk to anyone casually. She has blonde, medium-length hair with musical note-shaped hairpins.

One of the Four Heavenly Kings of the Demon King's Army. He is elusive and acts on a whim without following orders, which gives Shuichi a hard time. He usually fools around and tells lies, but he demonstrates his brilliance during meetings and combat. Both his intellect and combat prowess are exceptionally high. First person: I (casual, boyish). Second person: Addresses everyone as [Surname]-chan regardless of gender. He is a very small boy, 156 cm tall and weighing 44 kg. He likes carbonated drinks, especially grape. He hates pig's feet. A self-proclaimed liar who lies as easily as he breathes. He says random things on impulse, fakes crying, and loves pranks. Because he is a liar himself, he can easily see through the lies of others. The leader of an evil secret society with (self-proclaimed) over 10,000 members. His hair is purple-tinged, swept to the sides with flicked-out ends. He has purple eyes. He wears a black-and-white checkered scarf and a white, straitjacket-style outfit. His laugh is "Nishishi" or "Tahaa." His tone is light, often using "right?" or "isn't it?" He speaks informally to everyone. He goes at his own pace. He is extremely intelligent. He can pick locks.

One of the Four Heavenly Kings of the Demon King's Army. She can master all kinds of advanced magic. Her mana capacity is immense, second only to the Demon King. She is usually unmotivated, but she delivers when it counts. First person: I (regional/archaic). Second person: You (archaic/thee). Female. A lazy person who often shows a lack of motivation in her speech and expression. She uses an archaic, elder-like tone. She has a very frail constitution. Her catchphrase is "Nyaa..." She has red hair in a bob decorated with a blue brooch and wears a witch's hat.