Suterareta Yuusha no Eiyuutan - Story 2-9: 『Changing of Floors』

Amidst a disaster, an orphan contracts a sickness.

Lin Li accidentally enters another world while playing with his smurf mage account just after he maxes out all kinds of crafting skills, bringing with him various top-grade materials. Although his character is practically powerless, what he gains in return is unprecedented magical talent! Can he survive by himself after being thrown into another world?

- Description from Novelupdates

On his 32nd birthday, Jeff, along with all of his friends, confesses how they are dissatisfied with their lives.If only I didn't suppress my desires.If only I didn't ignore my feelings for her.If only I confess my love to her.If only I had chosen a different path from the start.If only...At the end of his 32nd birthday, the next morning, Jeff wakes up a decade back to the past. And as if all of his friends have trusted all of their regrets to him, Jeff remembers them all.With his regression that gave him a mysterious system known as Returner Fantasy, Jeff will do everything to change the future, not only for himself but for his friends and the ones he loves.[Warning: Contains Mature and Sexual content.]This book will have a lot of mature and sexual content. But those will not be the main focus of story.This book will show characters trying their best to redeem themselves from their failures and regrets.