A girl with bright blonde hair, characterized by a cat-like mouth. She used to have long hair as a child, but following a certain incident, she cut it into a bob. She has a bright and sociable personality. She generally speaks in polite language mixed with casual speech, though she occasionally uses foul language. She is a vegan; due to trauma, she can no longer stomach meat (she supplements missing nutrients with vitamins). She fights using the miracle of water manipulation. She mainly generates cubes in mid-air to use as footholds, restraints, or for attacks. Furthermore, she can manipulate the opponent's bodily fluids, such as blood. Her skill is considerable. While using her abilities, the angelic power erodes her life, significantly shortening her lifespan. It is estimated that by sacrificing her entire remaining life, she could stall even Satan for five minutes. The "he" that Rhea invited in was actually the Demon Lord Beelzebub. The villagers were brutally murdered by Beelzebub, and Rhea was imprisoned within a barrier. There, Rhea learned that he truly was a Demon Lord and that she had been the trigger for the village's tragedy. On the tenth day, driven to extreme starvation, Rhea finally consumed the meat offered to her—her own younger brother, Leo. She was later rescued when an exorcist unit led by Mother Rosa broke in, becoming the village's sole survivor. Using this tragedy as a catalyst, Rhea swore revenge against Beelzebub. She volunteered to become an exorcist and has since made significant contributions to the Church.

The Demon Lord governing the sin of Envy. Female. First person: I (Watashi) or "Mama." The mother of beasts living in the sea, she is originally the "King of the Sea" in the form of a giant whale. Out of a desire to make friends, she began mimicking the form of a weak, small girl. Because of her overwhelming power, she suffers from loneliness and harbors the feeling that "everyone else is lucky to be made so weak." Among the Demon Lords, she is particularly close to Asmodeus, and they call each other by the nicknames "Asmode-chan" and "Levi." She possesses top-tier combat strength among the Demon Lords; in her true form, she uses her massive size and physical strength as weapons, protected by a hard skin.

The Demon Lord of Lust. First person: I (Watashi). Like the other Demon Lords, she was originally a high-ranking angel. Her upper body is that of a glamorous woman, but her lower body is a grotesque form composed of animal heads and giant eyes. As her title suggests, she governs carnal desire and sexual impulses. While her direct combat ability is not particularly high compared to other Demon Lords, she boasts powerful aphrodisiac and mental corruption abilities; it is said that in the 17th century, she reduced numerous convents to brothels.

The Demon Lord of Greed. Appears as a man in a suit wearing glasses. He converts people's desires into his own magical power. First person: I (Ore, rough). He has a highly discriminatory and misogynistic personality, obsessed with manliness. However, he values his subordinates even if they are women (saying "Women are objects, but subordinates are comrades"), so his subordinates are fiercely loyal. He has high combat power but isn't very clever, sometimes allowing his activities to be exploited. He is often treated as a character who fails immediately after appearing. His weapons are the five rings on his left hand; for example, the symbol of "Treasure" manifests a diamond spear, while the symbol of "Technology" fires a barrage of missiles and firearms. In terms of combat style, he has a macho mindset that prefers one-on-one duels and bare-knuckle brawling.

The Demon Lord of Wrath. The ruler of Gehenna and the de facto leader of the Demon Lords and demons. First person: I (Boku, soft/polite). A black-haired young man with a snake wrapped around his neck. He has a soft-spoken manner. His pure combat power is apparently quite high, with strength equal to or greater than Leviathan's. He possesses a replica of Michael's sword, and it is said that as long as it is in Satan's hands, it is difficult for other demons to defeat him.

The Demon Lord of Gluttony. Appears as a middle-aged man. First person: I (Wagahai, archaic/pompous). He appears gentlemanly with the dress and speech of royalty or nobility, but his true nature is the cruel and hideous "Lord of the Flies." In addition to his raw strength, he is characterized by the trait of "growing stronger the more he eats."