I Kept Pressing the 100-Million-Year Button and Came Out on Top, Vol. 2 (manga) — Syuichi Tsukishima

After honing his swordcraft in an alternate world for over a billion years, Allen Rodol has finally achieved his dream of getting into Thousand Blade Academy. But nothing is quite going according to plan -- he suddenly finds himself living with a princess as his servant, and all his classmates hate him! It's up to Allen to sort out his academy life before the Elite Five Holy Festival, where he'll need to duke it out with gifted first-years from the other Elite Five Academies. In the face of overwhelming talent, will Allen's unparalleled dedication manage to come out on top?!