After being reincarnated into a fantasy world, a person finds themself reborn as Yuurai, an immortal witch lich with the appearance of a young silver-haired girl. She has no memory of her past life's crimes, yet she is immediately captured by the knights of the Rivalt Kingdom on charges of murdering and defiling the second princess. Thrown into a dungeon and subjected to brutal torture, Yuurai is forced to activate a hidden skill, Descend into Darkness. The skill consumes the souls of twenty thousand townspeople, transforming her into a terrifying Demon Lord of immense power. Now marked as a mortal threat, she becomes the target of holy knights, elite adventurers, and eventually the entire kingdom's army of ten thousand soldiers. All Yuurai wants is a quiet, peaceful life, but every attempt to withdraw only deepens the cycle of violence. With no way to prove her innocence and no hope of being left alone, she reluctantly embraces her dark role. Along the way, she gathers a small retinue of outcast women: Clare, a former holy knight who becomes bound to her through a magical oath; Lipia, a mage of the eyeless tribe; and Gilca, a beastwoman. Together they carve out a bloody existence in a world that refuses to tolerate them, as Yuurai navigates the line between protecting her newfound comrades and succumbing to the monstrous power within her. The narrative follows her rise from an innocent victim to a feared demon lord, touching on themes of survival, sacrifice, and the desperate pursuit of an ordinary wish amid extraordinary cruelty.