Moto Sekai 1-i no Sub-Chara Ikusei Nikki: Hai Player, Isekai wo Kouryakuchuu!  

The Former Top 1's Sub-Character Training Diary: A Dedicated Player is Currently Conquering Another World!, 元・世界１位のサブキャラ育成日記 ～廃プレイヤー、異世界を攻略中!～, Moto Sekai 1-i no Sub Chara Ikusei Nikki: Hai Player, Isekai wo Kouryaku-chuu!, The Former World Number 1's Alt Character Training Diary

The protagonist who spent most of his time playing video games during middle school and high school, is still unemployed as an adult. He was ranked first worldwide in these games and saw them as the meaning of his life. One day, he discovers that his character has been hacked and all data is unrecoverable. Overwhelmed with despair after losing everything he had worked for in a world that controlled him, the protagonist attempts suicide. When he wakes up, he finds himself inside the video game but it turns out to be a real-world version of it. He notices that he has reincarnated into the body of a sub character he created and bought premium benefits for long ago but neglected.