Warcraft: The Undead Scourge

“I am the lord of the undead; the nightmare that spreads death; the culprit behind the destruction of kingdoms; the source of all evil; a monster that cannot be forgiven and must be destroyed!

That’s how all the so-called ‘righteous’ people in the world describe me. Do they want to boil my bones for soup, too?” Standing atop a mountain peak, Marvin looked down over his empire and couldn't help laughing. “I only wanted to bring a little change to this world.”

…

This is really just the story of a transmigrator who brings along the base of Warcraft's Undead faction and gradually changes the world.