Oops, I Maxed Out the Tyrant's Obsession Meter

Ovidia Vencenza's new life began on an ordinary morning that went horribly wrong: she burned her breakfast toast, found a cursed assassin's dagger pinned to her bedroom door, and cheerfully assumed the local milkman was just having a bad day. Transmigrated into the grimdark world of Altamare, she adopted Nereo - a starved boy subjected to horrific abyssal magic experiments. Her brilliant survival plan? Train him into a legendary knight, sponsor his career, and safely retire on his royal pension with her frail younger brother, Tullio. Fast forward ten years. Nereo has returned from the borderlands not as a dutiful paladin, but as a towering, blood-drenched tyrant who slaughters anyone looking at Ovidia for too long. Told through alternating third-person perspectives between Ovidia's bubbly pragmatism and Nereo's terrifying inner monologues, the horrifying truth finally dawns on her. Ovidia drastically misunderstood the rules: the 'affection points' she farmed were actually 'corruption points.' Worse, Cosima, the supposed holy saintess, is a manipulative fraud framing Ovidia for heresy. Now, a maxed-out Nereo is threatening to shatter the continent into dust if Ovidia even mentions moving to the countryside without him. Can she fix a world-ending yandere before he burns down the kingdom in the name of love?