I Am the Last Villainess He Has to Kill

In a world where isekai’d souls usually become noble ladies, she awakens as the ultimate nightmare: the Demon King’s daughter and the final boss the hero must slay. Trapped in a brutal realm of monsters for five millennia, her only hope is to survive until the original plot unfolds. But then comes the twist—she adopts the future hero, Kiel, as a child. Now, she must raise the same boy who is destined to kill her. Can she change a predetermined fate, or is she raising her own executioner? Dive into the darkness and discover the truth in Chapter 1!