He Who Fights With Monsters 6 by Shirtaloon

The protagonist continues his rise from amnesiac outsider to a formidable power, juggling empire-building, tactical warfare, and the personal costs of leadership as new, supernatural threats and political rivals force him to stretch his growing abilities. Between brutal battles, clever use of the world's game-like rules, and uneasy alliances, he pursues greater knowledge and strength while confronting betrayals and moral dilemmas that will shape his future.