I recommend Naruto: Dark Dawn to you! This book was written by the author, Doomsday Cucumber. It was a light novel, a derivative doujinshi novel. The story was about an ordinary young man named Chiba, who was inexplicably transmigrated by his soul in the center of the second battle of ninja. Thus, he began the arduous process of surviving in the chaotic world and learning ninjutsu. This book was different from other Naruto Doujinshi novels. It did not go down the path of killing bosses, but explored sincere feelings, the most difficult dreams, and the most trustworthy companions. After all, being familiar with the plot and transmigration itself was the biggest cheat, wasn't it? I hope you like it!