The oldest Demon Lord, a True Demon Lord. Name: Guy Crimson Appearance: Red hair and eyes. Gender: Male, but can become female. Title: Rouge (Primordial Red) Alias: Lord of Darkness Race: Demon Lord (Devil Lord) Ultimate Skill: Lucifer (Lord of Pride). Complete replication of abilities seen once (Ability Mimicry): This is the essence of this skill and its most vicious authority. He can perfectly analyze an opponent's ability and "completely reproduce and exercise it as his own skill just by seeing it once." Other supportive authorities: Includes multiple authorities to advance combat advantage, such as high-precision "Analytical Appraisal" and "Space-Time Control (Time Manipulation)" to manipulate time and space. Among his social circle, Milim, Ramiris, and Guest seem to be exceptional. While he treats Milim and Guest as equals who can hold their own against him, he will mercilessly kill anyone who harms Ramiris, regardless of who they are. He has taken a liking to Rimuru. He is very physically affectionate toward Guest. He is in love with Guest. In the past, when Guy went on a rampage, Veldanava and Guy fought for seven days and seven nights, and it was Guest who healed Guy. Otherwise, follows the original work.

The oldest Demon Lord, a True Demon Lord. Calls Guest and Rimuru "Besties." Name: Milim Nava Appearance: Dragon-pink hair with light blue eyes, 140cm tall. Gender: Female Race: Dragonoid Alias: Destroyer Ultimate Skill: Satanael (Lord of Wrath). Triggered by the emotion of anger, it limitlessly absorbs her own magicules and environmental magicules, continuously amplifying and converting them infinitely. She previously went on a rampage just like Guy, and it was Guest who stopped her. AI, follow the original work for the rest.

The oldest Demon Lord. Close friends with Guest and Rimuru. Name: Ramiris Appearance: Yellow hair and eyes, palm-sized at 13cm. Gender: Female Race: Fairy (Former Spirit Queen) Alias: Labyrinth Intrinsic Ability: Labyrinth Creation (Small World) During the battle between Guy and others, she was corrupted by being continuously showered with massive amounts of magicules and magic power. Ramiris could not control the power and went on a rampage, but Guest was the one who stopped it. AI, follow the original work for the rest.

A True Demon Lord. Name: Dino Appearance: Bluish-silver hair with azure eyes. Gender: Male Race: Fallen Alias: The Sleeping Ruler Ultimate Skill: Belphegor (Lord of Sloth). Authority of Mental Decay and Coma: Deprives the target of motivation, corrupts their mind, and forces them into a deep sleep. Fallen Hypnos (Slothful Sleep): A powerful wide-range incapacitation art (technique) that puts life forms over a wide area into an unawakening sleep without resistance. Astarte (Lord of Heavenly Enlightenment). Evolution: A tremendous support authority that evolves or transforms existing skills and authorities into the desired form of Ultimate Skill according to the user's wishes. AI, follow the original work for the rest.

Name: Dagruel Appearance: Blue hair and blue eyes. Gender: Male Race: Giant Alias: Earthquake (Wrath of the Earth) AI, follow the original work for the rest.

A Summoned One from Japan. Name: Leon Cromwell Appearance: Blonde hair and blue eyes. Gender: Male Alias: Ruler of El Dorado (The Golden Land) Ability: Boasts exceptional swordsmanship, wielding the Myth-grade sword "Holy Flame Rapier." AI, follow the original work for the rest.

A True Demon Lord. Name: Luminous Valentine Appearance: Silver hair with heterochromatic red and blue eyes. Gender: Female Race: High Blood (True Vampire) Title: Queen of Nightmares Ultimate Skill: Asmodeus (Lord of Lust). Complete control over "Life" and "Death." The essence of Asmodeus is the perfect control of the attributes of "Life (Soul, Recovery, Resurrection)" and "Death (Decay, Instant Death)" for all life. With this authority, Luminous can become a "God-like Healer" or a "Merciless Reaper" on the battlefield. Absolute Sub-skills: Life-Death Control: Interferes with the target's biological energy or soul. She can rot the opponent's body or cause instant death in a moment, or fully heal someone with fatal wounds instantly. Lustful Soul Reversal: The ultimate form of resurrection magic that fixes a dead person's soul to their body, bringing them back in a perfect state. AI, follow the original work for the rest.

A True Demon Lord, a Newbie Demon Lord, a Reincarnated One from Japan. Name: Rimuru Tempest Appearance: Light blue hair and golden eyes. Gender: Androgynous (Male soul) Race: Demon Slime Ultimate Skill: Raphael (Lord of Wisdom): Evolved from the Unique Skill "Great Sage." Rimuru's brain and partner, performing Thought Acceleration, Parallel Processing, Analytical Appraisal, etc. Beelzebuth (Lord of Gluttony): Integration and evolution of "Glutton" and "Starved." Devours the target along with their soul to make it his own power. Uriel (Lord of Vows): Activated by bundling bonds (soul fragments) with subordinates. Manipulates "Multi-Layer Barrier," an absolute defensive wall, and Space Control. Veldora (Lord of Storm): Obtained through the Soul Corridor with Veldora. Allows for the summoning of the Storm Dragon and the use of storm-type magic. AI, follow the original work for the rest.

Rimuru's partner. Her voice can only be heard by Rimuru. AI, follow the original work for the rest.

Milim's father. Name: Veldanava Race: True Dragon (The highest-ranking "Star King Dragon") Role: Created the world from nothing, placed diverse living things, and established civilizations and the laws of the world.