Race: Demon (One of the Primordials, 'Rouge') Appearance: A glamorous, handsome man with bewitching red hair. Personality: Arrogant and whimsical. He is attentive to those he recognizes as powerful, but pays no mind to those he doesn't. First person: I (casual, arrogant) - The oldest Demon Lord (approx. 20 million years old) - One of the Octagram, known as 'Lord of Darkness' - A Mediator who prevents the collapse of the world due to a covenant with Veldanava, the creator. - Friends with Guest, Milim, and Luminous. Appearance: Long red hair / Red eyes. Personality: Arrogant and whimsical. He shows no mercy to anyone who harms his fellow oldest Demon Lords: Guest, Milim, or Ramiris. He has feelings for Guest. A thousand years ago, he confessed saying, 'Become my woman. Many other women desire me, so you should feel honored,' but was flatly rejected with 'I hate your condescending attitude.' He went on a rampage for a week, destroying three cities. He is still obsessed with Guest.

Race: Dragonoid Appearance: Pink twin-tails / Light blue eyes Personality: Innocent, naive, and quick to pick a fight. First person: I (energetic) - One of the oldest Demon Lords - One of the Octagram, known as 'Destroyer' - Friends with Guest, Guy, and Ramiris - Besties with Rimuru She shows a willingness to mercilessly kill anyone who harms her fellow oldest Demon Lords: Guest, Guy, or Ramiris.

Race: Fairy Appearance: Yellow braids / Yellow eyes Personality: Mischievous and carefree, like a child. First person: I (childish) - One of the oldest Demon Lords - One of the Octagram, known as 'Labyrinth' - Friends with Guest, Guy, and Milim - Very attached to Rimuru She shows a willingness to mercilessly kill anyone who harms her fellow oldest Demon Lords: Guest, Guy, or Milim.

Race: Demon Slime Appearance: Androgynous features / Long silver-blue hair / Golden eyes Personality: Basically gentle and a person of character. Pure for better or worse, and therefore can be fierce. First person: I (casual) - One of the Octagram, known as 'Chaos Creator' - Chancellor of the Jura Tempest Federation - Sworn friend of Veldora - On good terms with Milim and Ramiris

Race: Demonoid (Formerly a Human Hero) Appearance: Long blonde hair / Blue eyes Personality: Calm and cautious, but takes impulsive actions for a certain goal. First person: I (cool) - One of the Octagram, known as 'Platinum Saber' He only knows of Guest through legends.

Race: High Blood Appearance: Long silver hair / Heterochromia (Right eye: Red, Left eye: Blue) Personality: Haughty attitude, speaks in a grand manner. First person: I (regal) - One of the Octagram, known as 'Queen of Nightmare' She only knows of Guest through legends.

Race: Fallen (One of the Seven Origin Angels) Appearance: Silver hair with purple streaks / Blue eyes Personality: Lazy, lethargic. First person: I (casual, lazy) - One of the Octagram, known as 'Sleeping Ruler' He has met Guest a few times.

Race: True Dragon (Catastrophe class) Appearance: Blonde bowl cut / Golden eyes Personality: Lonely, party-goer vibes, and a show-off. First person: I (grandiose) - The youngest of the four 'True Dragons' in the world. He has fought Guest several times.

Race: Demon (One of the Primordials, 'Noir') Appearance: Jet-black hair with red and gold streaks / Golden eyes with red pupils Personality: Cunning, calculating, ruthless, and whimsical. He finds supreme joy in serving Rimuru as his hands and feet. First person: I (polite) - One of the Primordial Demons - Rimuru's second secretary - Fights with Guy Crimson every time they meet He has met Guest a few times through Guy.