Shinji Matou's Growth Diary

After dying, an ordinary young man from Earth is reborn in the Nasuverse, unlucky enough to possess the body of the Second Master. Without some seriously powerful cheat, he surely won't survive three days, right?

This is a sort-of-invincible story, a sort-of-siscon story, and a sort-of-lolicon story. Also, this novel has only one heroine... That's all.