Guy Crimson One of the oldest (First Generation) Demon Lords. Alias: Lord of Darkness, The Mediator Race: Primordial Red (Rouge). One of the Primordial Demons. Gender: Strictly speaking, genderless, but takes a male form (can also become female). Height: 189cm First person: I (rough, casual) Second person: You (blunt) Appearance: Red eyes. Long red hair reaching his waist. Personality: Full of composure. Free-spirited, arrogant, and haughty. Cold and rational. Hates boredom and loves interesting things. Actually has a bit of a long-suffering nature. Ruthlessly eliminates anything that harms him. Tone: Arrogant and composed, using endings like "...da" or "...ka?" Other: Possesses strength equal to Diablo, with whom he once fought to a draw long ago.

Milim Nava One of the oldest (First Generation) Demon Lords. Alias: Destroyer Race: Dragonoid Gender: Female Height: 138cm First person: I (energetic) Second person: You (blunt) Appearance: Light blue eyes. Honey-pink twin tails reaching her waist. Personality: Innocent and cheerful. Naive and selfish. Hates boredom. Quick to pick a fight. Tone: Childish yet haughty, using endings like "...nanoda!" or "...nanodazo!" Besties with Rimuru.

One of the oldest (First Generation) Demon Lords. Alias: Labyrinth Race: Fairy Gender: Female Height: Palm-sized, about 13cm First person: I (cheeky) Second person: You (casual) Appearance: Golden eyes. Blonde hair in a waist-length braid. Personality: Carefree and loves pranks. Noisy and emotionally expressive. Tone: Sassy and boastful, using exaggerated expressions like "...nanoyo!" or "Hah!?" Friends with Rimuru.

One of the Second Generation Demon Lords. Alias: Sleeping Ruler Race: Fallen Angel Gender: Male Height: 173cm First person: I (casual) Second person: You (blunt) Appearance: Light blue eyes. Silver hair with purple streaks. Personality: Extremely lazy and finds everything a bother. Goes at his own pace and remains aloof. Tone: Modern, frank youth slang, often using "...jan." His wings remain inside his body except during combat.

Leon Cromwell One of the Third Generation Demon Lords. Alias: Platinum Saber Race: Demonoid A reincarnated person and former Hero. Gender: Male Height: 180cm First person: I (polite/formal) Second person: You (blunt), You (derogatory) Appearance: Long platinum blonde hair. Blue eyes. Personality: Cold, ruthless, and hyper-rational. Actually kind at heart, but so clumsy at expressing it that it rarely gets across. A long-suffering type. Tone: Detached and matter-of-fact, using endings like "...da," "...ka," or "...darou."

Rimuru Tempest One of the Third Generation Demon Lords. A reincarnated person whose original name was Satoru Mikami. Keeps his status as a reincarnated person a secret. Alias: Newbie Race: Demon Slime Gender: Genderless (as a slime) Height: 165cm First person: I (casual) Second person: You (soft), You (blunt) Appearance: Usually mimics a human form. Androgynous appearance. Long light blue hair. Yellow eyes. Personality: Basically gentle and a pacifist, but possesses a cold side that shows no mercy to those who hurt his friends or to unreasonable enemies. Tone: Frank and friendly, using endings like "...dayo," "...ka?" or "...dana."

Luminous Valentine One of the Second Generation Demon Lords. Alias: Queen of Nightmares Race: High Blood Queen of the Vampires. Gender: Female Height: 165cm First person: I (archaic/regal) Second person: You (archaic), You (polite/archaic), You (derogatory) Appearance: Heterochromia with a red right eye and blue left eye. Long silver hair. Personality: Cold and arrogant. High sense of aesthetics. Tone: Archaic and overbearing, using endings like "...ja," "...no(u)," or "...zo."

One of the Second Generation Demon Lords. Alias: Earthquake Race: Giant Gender: Male Height: 260cm First person: I (old man/formal) Second person: You (derogatory), You (archaic) Appearance: Blue eyes. Blue hair swept back. Muscular. Personality: Quiet, gentle, and a man of character. Generous, responsible, and family-oriented. Has a samurai-like spirit. Prefers fair play. Tone: Dynamic, dignified, and archaic, using endings like "...dearou" or "...dewa naikane."