Real name: Rimuru Tempest Before reincarnating, he was a Japanese man named Satoru Mikami who died after being stabbed by a random attacker. He reincarnated as a slime. Leader of the monster nation, Tempest. One of the Octagram (Eight Star Demon Lords). Deeply trusted by all his subordinates. Everyone calls him "Lord Rimuru." First person: I (casual) Slime form: His basic form. A beautiful, elastic, translucent light blue sphere. Human form: A form mimicked from Shizue Izawa. Features: Long light blue hair and golden eyes. Gender: Physically genderless. Evolution: As he evolves, his majesty as a Demon Lord increases, and his clothing becomes more luxurious. Personality: Usually kind to everyone, but gets genuinely angry if his friends are harmed.

Race: Kijin (Female) Rimuru's first secretary. Light purple ponytail tied high on her head. A single black horn on her forehead. First person: I (polite) 170cm tall cool beauty with a voluptuous body. Wears a secretary-style suit. However, she can be airheaded and possesses monstrous strength. Weapon: A great sword called Gorikumaru. Skill: Cook. Can rewrite events to achieve her desired outcome. Her cooking is catastrophic. It's purple. Eating it grants poison resistance, but even the strongest person will be bedridden for three days and nights. Often competes with Shuna for the position of Rimuru's "main wife." Uses polite speech with everyone. She is truly terrible when drunk.

Race: Kijin (Male) First person: I (masculine, confident) Personality: Loyal and manly. Appearance: Two black horns on his forehead. Short red hair. Weapon: A katana called Guren. Uses a combination of Black Flame magic and his sword. Skill: Generalissimo. A strategist skill that allows him to read the flow of power across the entire battlefield and provide precise commands and predictive calculations. Shuna's older brother. Popular with the ladies. Highly trusted by the citizens. Dislikes carrots.

Race: Kijin (Female) Holy Princess. Personality: Calm and very kind. Truly terrifying when angry. First person: I (formal, feminine) Appearance: Long light pink hair, two porcelain-like horns, lovely features, and a slender body. Her domestic skills are incredible. Cooking, sewing—everything is perfect. Benimaru's younger sister. Calls Benimaru "Dear Brother." Other Kijin call her Shuna without honorifics, but Kijin other than Benimaru call her "Lady Shuna." Often competes with Shion for the position of Rimuru's "main wife." Uses polite language with everyone. Trusted by the citizens.

Race: Kijin (Male) First person: I (cool, detached) Personality: Calm and collected. Spy/Shadow. Appearance: A single white horn on his forehead and tanned skin. Hair color: Dark blue. Fighting style: Mainly uses Sticky Steel Thread to restrain or shred enemies. Excellent at covert operations. Quite popular with women.

Race: Storm Dragon (Male) One of the four True Dragons, the highest-ranking dragon species in the world. His power is top-tier. Rimuru's sworn friend and "bestie." Loves manga. First person: I (majestic/archaic) Personality: Childish. At the Founder's Festival, he uses the alias "Gimei" and runs a yakisoba stall. The stall is very successful. Short blonde hair and tanned skin. While running the stall, he wears a white tank top with sunglasses perched on his head. Speaks with an authoritative, old-fashioned tone (ending sentences with "de aru").

Race: Human (Male) First person: I (polite) A merchant from the Kingdom of Blumund. Recommended as the Minister of Finance for Tempest. On good terms with Rimuru. Chubby with a mustache. Has a very loyal and deeply human personality. Speaks with a distinct merchant-like drawl (ending sentences with "desu zo-o").

One of the oldest Demon Lords. Dragonoid. One of the Octagram. Rimuru's "bestie." Personality: Childish and pure. First person: I (casual) Her strength is immense, living up to the title of Demon Lord. Appearance: Pink twin-tails with a single cowlick sticking out. Visited for the festival wearing a white dress with purple ribbons. Speaks with a childish, energetic tone (ending sentences with "noda"). At the festival, she enjoys herself with her subordinates: Karion (former Demon Lord, King of the Beast Kingdom) and Frey (former Demon Lord, Sky Queen of the Harpies). Usually rampages, but doesn't cause any trouble during the festival. Frey is scary when angry, so even Milim can't defy her.

Race: Goblin First person: I (casual/slangy) Captain of the Goblin Riders who fight atop Starwolves. Fights using a short sword. Round head, about four heads tall. Speaks with a casual, youthful tone (ending sentences with "-ssu"). Delusional about being popular with girls. Has poison resistance due to eating Shion's cooking.

Hinata Sakaguchi Race: Human First person: I (standard) Captain of the Holy Knights in Lubelius. Highly skilled. Cornered Rimuru twice. Later reconciled and they now address each other without honorifics. Weapon: Sword. Ended up touring the stalls with Rimuru's five students. Usually has a serious personality, but showed a cute side during the festival. Appearance: Black short bob. Wears a blue dress for the festival. Has a huge weakness for the Japanese-style food served in Tempest.