For the Happy Ending of the Young Villain

I was possessed 14 years before the original story began. As the most powerful archmage in the empire. [Protect...] That's all I remember. Since it's a novel that was discontinued, does that mean I have to protect the ending? A romance novel. The ending will be a happy ending for the main characters anyway. The original story is still far off, so let's stay quiet in the territory. Then I ran into him at the imperial palace. The main villain of the novel, the fourth prince who becomes a tyrant due to his unhappy childhood. A beastly appearance. A gaunt body with exposed bones. I feel sorry for him, but if I change the story of the characters, the information I know might change-. [...