Sienna, once the world's top assassin, was reborn in another world as a powerless girl betrayed by her best friend. She crossed paths with Callum, the Lord of the Demon Realm, and the two were unexpectedly bound by a mark, forcing them to live and die together. As Sienna's spiritual power gradually returned, she entered Azure Schola to study, though everyone still saw her as a useless waste. During the Trial Month, she proved everyone wrong with her true strength, took revenge on her treacherous ex-boyfriend and fake friend, and with Callum by her side, grew into a high-ranking mage.
