Seduce the Villain's Father

Story:

After the accident I woke up in the body of one of the heroines of my favorite web story, but I moved to the novella before the main events, where so far there are only parents of the main characters. To prevent a series of events, I'm trying to stop my sister's abduction. But instead, they're kidnapping me! I'm about to die because my body can't cope with mana. But when I meet the abductor emperor, mana calms down next to him. To prevent the emperor from marrying a witch and killing the emperor by his future son, and to save myself from terrible mana. I must marry the Emperor.