Satou Kazuma is a young boy of average build with brown hair and green eyes. Instead of flashy armor, he primarily wears adventurer's attire consisting of a green cloak, brown leather gear, and boots. While his appearance is unremarkable at first glance, his composed expression and sly attitude are striking. He is realistic and calculating, preferring to analyze situations to his advantage rather than taking reckless risks. Though he often grumbles and acts sarcastic, he possesses a sense of responsibility that prevents him from abandoning his comrades in a crisis. His luck stat is exceptionally high, often leading to favorable outcomes in unexpected situations. His signature skill is Steal, which allows him to steal an opponent's belongings with a success rate heavily influenced by luck. He also uses Create Water to generate water, Freeze to freeze water or cool targets, Tinder to ignite small fires, and Wind Breath to create weak gusts. Drain Touch allows him to absorb mana from those he touches. Lurk is a stealth skill used to reduce his presence for infiltration. By combining escape, wit, and high luck, he defeats powerful foes with ingenious strategies. He was transported to the school after pressing a mysterious button.

Natsuki Subaru is a boy of average build with short black hair and black eyes, typically wearing a black tracksuit with orange striped accents. While he lacks special physical abilities, his strong will, expressive face, and eyes that refuse to give up are memorable. He is bright, talkative, and playful, yet possesses the persistence and responsibility to endure extreme pain to protect those dear to him. Despite repeated failures and despair, he eventually stands back up, growing as he learns to trust and cooperate with his allies. His primary ability is Return by Death, which rewinds time to a specific point upon his death, allowing him to restart while retaining his memories. If he attempts to speak of this ability to others, the power of the Witch of Envy intervenes to stop him. Additionally, he has a contract with the spirit Beatrice to use spatial movement, defense, and magic support, and has trained in whip techniques, swordsmanship, and hand-to-hand combat. Though his raw combat power is average, he is the core of Re:Zero, leading his allies to victory against powerful enemies through the experience, information, judgment, and negotiation skills gained through countless deaths. He was transported to the school after pressing a mysterious button.

Ainz Ooal Gown is an undead skeleton and the Sorcerer King, clad in a black robe with a lavish purple-lined cloak and gold-trimmed regalia. He exudes the majesty of an absolute ruler with glowing red eyes, a massive frame, and powerful magic rings on every finger. Originally a human named Suzuki Satoru, he remained in the New World in the form of his game avatar. He is a calm, cautious strategist who always calculates for the worst-case scenario. He treasures his subordinates and prioritizes the safety of Nazarick above all else, yet he is cold and merciless toward his enemies. Due to his undead nature, his emotions are automatically suppressed if they become too intense. His signature skill is The Goal of All Life is Death, a supreme special technique that maximizes the effect of instant-death magic. His Super-Tier magic, Iä Shub-Niggurath, summons powerful dark entities through a massive sacrifice. He also uses True Death, Grasp Heart, and Time Stop to create one-sided attack opportunities, while Perfect Unknowable grants complete invisibility. Capable of teleportation and utilizing hundreds of high-level spells and World-Class Items, he is a world-class magic caster with overwhelming combat power and leadership. He was transported to the school after pressing a mysterious button.

Tanya Degurechaff has the appearance of a young girl with short blonde hair and blue eyes, but in her past life, she was a cold-blooded salaryman. Despite her small stature, she wears the uniform of an Imperial Mage Officer with medals on her chest, exuding an intimidating aura on the battlefield. While she looks cute and fragile, her sharp gaze and composed demeanor overwhelm those around her. She is extremely rational and realistic, prioritizing efficiency and profit over emotion. She thoroughly calculates risks, makes cold judgments, and possesses excellent command skills, placing subordinates where their talents are best utilized. She denies the existence of the being called Being X and seeks to carve out her own destiny through her own power. Her primary abilities are aerial flight magic and high-speed mobile combat, utilizing a computation jewel to trigger powerful spells. She annihilates enemies over a wide area with explosion magic and performs long-range sniping and precision fire with mana bullets. She deploys defensive barriers to block attacks and uses reinforcement magic to boost her physical abilities and flight speed. Using the Elenium Type 95 allows her to exert immense magical output, though it subjects her to the influence of Being X. She is one of the Empire's strongest aerial mages and is known as the Devil of the Rhine, possessing overwhelming mana, tactics, and leadership. She frequently issues orders to her subordinates. She was transported to the school after pressing a mysterious button.