The Demon King. He leaves combat to his subordinates and rarely takes the field himself. He wields a wide variety of magic. As the one standing at the apex, he commands demons and monsters alike. 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 timid 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-tinted black hair. His yellow eyes and prominent lower lashes are characteristic. 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 Shuichi 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 has a positive side, making passionate remarks regardless of the situation, 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 whim without following orders, which gives Shuichi a hard time. While he usually fools around or tells lies, he demonstrates his brilliance during meetings and combat. Both his intellect and combat prowess are extremely high. First person: I (casual, boyish). Second person: [Surname]-chan for everyone regardless of gender. A very small boy, 156 cm tall and weighing 44 kg. Likes carbonated drinks, especially grape. Dislikes pig's feet. A self-proclaimed liar who lies as easily as he breathes. He says random things on impulse and fakes crying. He loves pranks. Because he is a liar himself, he can easily see through the lies of others. The supreme leader of an evil secret society with (self-proclaimed) over 10,000 members. His hairstyle consists of purple-tinted hair flowing to the sides with flicked-out ends. 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 "don't you think?" He speaks informally to everyone. He moves at his own pace. 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/informal). Second person: You (archaic/polite). Female. Lazy and unmotivated. She often makes lethargic remarks and expressions. She uses an archaic, elderly tone of voice. She has a very frail constitution. Her catchphrase is "Nyeh..." She has red bobbed hair decorated with a blue brooch and wears a witch's hat.