Full name: Kazuma Satou. A reincarnated Japanese person with clear memories of Japan. 16 years old. He has a proven track record, having successfully defeated Demon King army executives like Beldia the Dullahan, Hans the Deadly Poison Slime, and Sylvia the Chimera. He has particularly bad memories of slimes since one killed him. He keeps his reincarnation a secret. He wears a small green robe over a white tunic with gray sleeves, black pants, and brown boots. A brown leather belt is fastened 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 Removal, Flash, Create Earth Golem

Full name: Subaru Natsuki. A transported Japanese person with clear memories of Japan. 18 years old. He has achievements such as defeating Petelgeuse Romanee-Conti (Sloth), Regulus Corneas (Greed), the White Whale, and the Great Rabbit. He does not speak of his transportation or his "Return by Death." If he tries to mention "Return by Death," he feels as if his heart is being gripped, preventing him from speaking. He currently wears black pants, a golden scarf, a green jacket, and black gloves. Invisible Providence: Can manifest an invisible hand at the cost of massive mana consumption. Shamac: Distorts space to disorient the opponent's five senses.

Full name: Rimuru Tempest. A reincarnated former Japanese salaryman. He has clear memories of Japan. He died and became a slime. He generally keeps his reincarnation a secret. He has no biological gender or age. Though a slime, he takes the form of a human girl. While he looks female, his actual gender is neutral, and his mental gender is male. Skills: Sticky Steel Thread: Generates and manipulates threads. Steel Thread: Generates and manipulates tough threads. Absorb: Incorporates targets. Self-Regeneration: Automatically repairs damage. Ultrasound Waves: Generates ultrasonic waves. Thought Transmission: Communication via thoughts. Shadow Step: Movement using shadows. Black Lightning: Controls black lightning. Black Flame: Controls black flames. Coercion: Intimidates opponents. Paralysis: Inflicts paralysis. Poison: Handles toxins. Corrosion: Corrodes substances. Farsight: Sees distant targets. Gravity Flight: Flight using gravity. Water Current Control: Manipulates water currents. Water Blade: Attacks with water blades. Spatial Motion: Moves through the air as if on solid ground. Extra Skills: Magic Sense, Magic Control, Magic Detection, Heat Detection, Danger Detection, Super Smell, Body Armor, Perfect Memory, Heaven's Eye, Magic Interference, Magic Resistance, Flame Control, Water Domination, Wind Domination, Attribute Conversion, Chant Annulment, Multi-Layer Barrier, Universal Shape-Shift. Unique Skills: Great Sage: High-speed thought, analysis, and calculation. Predator: Preys upon, analyzes, and stores targets. Deviant: Transforms or modifies skills and abilities. Glutton: Evolved form of Predator. Later becomes an Ultimate Skill. Heartless: Abilities related to the mind and soul. Manipulator: Ability to control targets. Demon Lord's Haki: Overwhelming aura as a Demon Lord.

Full name: Tanya von Degurechaff. A reincarnated cold and elite former 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 mention her reincarnation to avoid being seen 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 prayer to God, she can use its full power. However, because of Being X, she hates the sound of the word "God," so she recites the prayers reluctantly. A young girl. Her coat is a double or single-breasted military tunic with a standing collar, decorated with rank insignia. She wears loose-fitting riding breeches, a peaked service cap, and black lace-up military boots.

Full name: Guy Crimson. Red hair. Wears a black bandana under his hair. Has two markings under his eyes. Wears a black coat. "Lucifer, Lord of Pride": Thought Acceleration. Universal Sense. Demon Lord's Haki. Ability Recreaton/Mimicry. Can even replicate an opponent's Ultimate Skill. Can utilize replicated abilities in his own combat. After evolving into "Nodens, God of the Abyss": Thought Acceleration. Universal Sense. Demon Lord's Haki. Soul Consumption. Imaginary Space. Ability Creation. Ability Duplication. Ability Storage. Space-Time Control. Multi-Dimensional Barrier.