I Got a Cheat Skill in Another World and Became Unrivaled in The Real World, Too 1 (manga) - Miku

Little, Brown & Company - <p>Yuuya Tenjou was fifteen years old and bullied since he was little-just for being ugly. But one day, he found a door to another world. Traveling between an alternate reality and the real world, Yuya turns his life around!</p>