The Insider System - Chapter 36: Alchemy

A teenager named Evan Mason was reincarnated into the magical world of Harry Potter and goes to school at Hogwarts!
With only his knowledge of the future and great talent for magic, he takes the path towards the top of the magic world, only to realize that ever step he took, changed everything!

- Description from Novelupdates

Arnold never thought his gaming skills would land him in a romance novel—as a doomed side character, no less. To survive, he hijacks the heroine's “system,” bending the story to his will. But when he dodges a deadly duel, he catches the eye of the heroine, Lara, his own step sister—and her love is a dangerous game. Arnold must outwit the plot and his step sister who's not afraid to kill for love. In this LitRPG romance gone wrong, survival isn't just about beating the system—it's about escaping the heart of a yandere.

Officer, if I told you this just was a “Healing-type Game,” would you believe me?

Orlax Tirshtain is the villain in the global game [Unification of Empires]. The tyrannical, cold-blooded emperor is a man who slaughtered his own family with his own hands and ascended the throne with their blood—a power-obsessed madman. Despite five years having passed since the game’s release, no one has been able to defeat this lunatic. So, how the hell did I become this damned?????