Isekai de Cheat Skill wo Te ni Shita Ore wa, Genjitsu Sekai wo mo Musou Suru: Level Up wa Jinsei wo Kaeta

Since a young age, Tenjou Yuuya was continuously bullied. He is staying in his beloved grandfather's home while he goes to school and, as usual, he receives a harsh bullying, and takes an extended absence from school in order to have some time to heal his wounds. While on this long time of absence, he takes the opportunity to clean his grandfather's house and finds a room he never had seen before.