Tensei Mae no Tutorial de Isekai Saikyou ni Narimashita.: Junbi Shisugite Daini no Jinsei wa Easy Mode desu!

Synopsis:

A 33-year-old man, exhausted from his life of bullying and workplace harassment, escapes into video games. However, after his death, he is chosen for reincarnation in another world. The woman guiding him to this new life informs him that no cheats will be granted, but instead, he will undergo three months of training at a special reincarnation facility. Though the facility is meant to help him quickly acquire skills, his progress is slow as he is thrown in before he has a chance to prepare. During those three months, he trains desperately to survive in his new world. But even after one year, then ten, he begins to doubt whether he is stuck in an infinite hell of the game world, a punishment for his past life of excessive gaming. What he doesn't know is that the reincarnation process was delayed due to a mistake made by the female guide. Fifteen years later, when he has transformed into an overwhelming force capable of slaying an ancient dragon, the reincarnation is finally complete. Now, the man, who has become nearly invincible, hopes to enjoy his new life in this world the right way—without resorting to his new overwhelming powers.