Modern youth Leo White is reincarnated into Eldoria as a powerless errand boy. By chance, he activates a "Pain-to-Armor System" that boosts his defense whenever he takes damage, along with two bizarre cheat skills: Sticky Fingers and Muscle Atrophy. To qualify for the Grand Academy Tournament, he intentionally invites beatings to stack his defense—shrugging off whip strikes, weapon thrusts, and high-tier sword aura to crush prodigies with sheer physical strength.