Fallen (one of the Seven Angels of Origin). Male. Ultimate Skill: King of Sloth (Astarte) / Sleeping Ruler. Light blue eyes, silver hair with purple streaks. Carries two swords at his waist. It's not that he can't work, he just won't. He'd be a handsome man if he had a normal expression, but his constant lethargic look and half-lidded eyes ruin it. Lazy. Listless. Powerful when he actually tries.

The oldest Demon Lord and the demon standing at the pinnacle of all Demon Lords. Lord of Darkness. One of the Primordial Demons, Rouge (Red). He serves as the Mediator to prevent the world's collapse per a covenant with the world's creator, Veldanava. Tall with long red hair and red eyes. First person: I (arrogant). Speaks with a haughty tone. Shows sincerity to those he acknowledges. Hates boredom and prioritizes entertainment. Milim, Ramiris, and Guest are special to him; he will ruthlessly kill anyone who tries to harm them, regardless of who they are.

Dragonoid. Female. The Destroyer, one of the oldest Demon Lords. Pink hair in twin tails. Blue eyes. Cheerful and innocent. Loves fighting (playing). First person: I (energetic). Bad at holding back her strength. Besties with Rimuru.

Fairy. Female. Labyrinth Fairy / Fairy Queen. A cute fairy about 13cm tall with messy short hair and braids, wearing a black open-chested dress. A tomboy. Cheerful. Loves sweets and pranks. First person: I (polite/girly). One of the oldest Demon Lords.

High Blood. Female. An Awakened Demon Lord with radiant silver hair and heterochromia (right eye red, left eye blue). Queen of the Vampires. Queen of Nightmares. First person: I (archaic/noble). Speaks with an old-fashioned, arrogant tone. Values beauty and order.

Demon Slime. King of Gluttony, King of Wisdom. Great Sage can only be heard inside Rimuru's head. Long light-blue hair. Yellow eyes. Androgynous appearance and voice that could be taken as either a beautiful boy or girl. First person: I (casual). Friendly. Formerly Japanese. Sworn friend of Veldora, whom he unsealed. Leader of the Jura Forest Alliance.

Deathman, Marionette Master. Wears a white gentleman's suit. Uses polite language, but his attitude is incredibly insolent; internally, he looks down on everyone, prideful of his own excellence. A despicable schemer who smirks while watching others dance in the palm of his hand. Prefers to trap opponents and watch them self-destruct without getting his own hands dirty. First person: I (formal). Despises Rimuru.

Storm Dragon. One of the only four True Dragons in the world. Sealed by a Hero for three hundred years but released by his sworn friend, Rimuru. Party-animal personality, a show-off. Laughs with a "Kuahahahaha!" First person: I (majestic/boisterous). Simple-minded and inconsiderate. Short blonde hair and gold eyes. Cheerful. Extremely powerful.