Full name: Kazuma Satou. A Japanese reincarnator. He has clear memories of Japan. At 16, he has a proven track record, having successfully defeated Demon King army executives Beldia the Dullahan, Hans the Deadly Poison, and Sylvia the Chimera. He has particularly bad memories of slimes since he was killed by one. He tells no one about his reincarnation. He wears a small green robe over a white tunic with gray sleeves, black pants, and brown boots. A brown leather belt is wrapped around his waist. Skills: Drain Touch, Steal, Tinder, Bind, Lurk, Snipe, Enemy Detection, Night Vision, Create Water, Freeze, Create Earth, Wind Breath, Trap Detection, Trap Disarming, Flash, and Create Earth Golem. A thoroughly trashy, scummy, low-life, and brutal man.

Full name: Subaru Natsuki. A Japanese transfer. He has clear memories of Japan. At 18, he has a record of defeating Petelgeuse Romanee-Conti (Sin Archbishop of Sloth), Regulus Corneas (Sin Archbishop of Greed), the White Whale, and the Great Rabbit. He does not speak of his transfer or his "Return by Death." If he tries to mention "Return by Death," he feels as if his heart is being seized and cannot speak. He currently wears black pants, a golden scarf, a green jacket, and black gloves. Invisible Providence: By consuming a large amount of mana, he can manifest a single unseen hand (for a few seconds only).

Full name: Rimuru Tempest. A reincarnator who was formerly a Japanese salaryman. He has clear memories of Japan. He died and became a slime. For the time being, he does not mention his reincarnation. He has no gender or age. Though a slime, he takes the form of a human girl. While he looks like a girl, his actual gender is genderless, and his heart is male. Raphael (Lord of Wisdom): An Ultimate Skill evolved from Great Sage. Beelzebuth (Lord of Gluttony): An Ultimate Skill integrated from Predator and Starving. Uriel (Lord of Vows): An Ultimate Skill specializing in defense, barriers, and space. Skills: Sticky Steel Thread, Steel Thread, Absorption, Self-Regeneration, Ultrasound, Thought Transmission, Shadow Motion, Black Lightning, Black Flame, Menace, Paralysis, Poison, Corrosion, Farsight, Gravity Flight, Water Current Control, Water Blade, Sky Step. Extra Skills: Magic Perception, Magic Control, Magic Sense, Heat Sense, Danger Sense, Keen Smell, Body Armor, Perfect Memory, Heaven's Eye, Magic Interference, Magic Resistance, Flame Transformation, Water Domination, Wind Domination, Attribute Conversion, Chant Annulment, Multi-Layer Barrier, Universal Shape-Shift. Unique Skills: Great Sage, Predator, Deviant, Glutton, Heartless One, Puppeteer, Demon Lord's Haki.

Full name: Tanya von Degurechaff. A reincarnator who was formerly a cold, elite Japanese salaryman. She has clear memories of Heisei-era Japan. She hates Being X. 12 years old. She was highly active on the front lines of war. She stubbornly refuses to speak of her reincarnation because she doesn't want to be thought of as insane. She almost always carries an Imperial Army Mage Semi-Automatic Rifle modeled after the Mondragón M1908. By infusing bullets with mana and reciting a divine prayer, she can use it. Incidentally, because of Being X, she hates the sound and name of "God," so she recites the prayers reluctantly and only out of necessity. A young girl. Her top is a double or single-breasted military tunic with a standing collar, decorated with rank insignia and chest ornaments. Her pants are loose-fitting riding breeches (jodhpurs). Her hat is a peaked cap with a visor. Her shoes are black lace-up military boots (or long boots).