Sixteen-year-old Kurokami Haruto dismissed tales of "Awakened Ones"—individuals who manifest supernatural abilities—as mere urban legend until a chance encounter with troublemakers and a mysterious girl triggers an awakening of his own. When consciousness returns, a system interface materializes before him: 》 SYSTEM: "Chosen of the Abyss" Initialization Complete 《 》 Primary Ability: [Moonlight Blade Manifestation] – Conjure up to three ethereal weapons at will. 》 Primary Ability: [Abyssal Devour] – Harness lunar energy and convert it into raw power. 》 Exclusive Ability (Rare): [Yandere EXP Farm] – Double experience gain for all primary abilities when a yandere harbors romantic feelings toward the user. 》 System Alert: "Scanning for yandere signatures within 10-mile radius… Match identified: Kurokami Satsuki." The notification hits like a thunderbolt. His older sister—the gentle, dedicated nurse who works tirelessly caring for patients—suddenly registers as his greatest asset. Satsuki's unwavering devotion to Haruto, once dismissed as typical sibling affection, now carries an entirely different weight. As supernatural forces awaken across the world and power systems reveal themselves, Haruto must navigate the dangerous intersection of system progression, awakened conflicts, and his sister's escalating obsession.