Source: https://kakuyomu.jp/works/16818093094471724561
Synopsis
Moriguchi Hiroto, a shut-in NEET with no friends and no girlfriend, is reincarnated into a gal game he loved in his previous life.
However, he is reincarnated as the protagonist’s best friend.
For a certain reason, he tries hard to follow the original story, but fate and the heroines won’t let him.
Even so, Moriguchi Hiroto doesn’t give up and continues to strive to fulfill his role as the best friend.
Side Story 1 – Epilogue (Niiro Sarasa)
Side Story 2 – Prologue (Hisada Haruka)
Volume 2 Epilogue (Hisada Haruka)
Volume 3 Prologue (Fumi-chan Senpai)