Board Thread:Episode Discussions/@comment-1181222-20170809100834/@comment-5085906-20170812183415

Why does it have to be a character that we know that wrote that book? It could have been a nameless historian who did his research. Sharingan knowledge was common even during the events of the OG Naruto and Mangekyo knowledge became common when almost every living Uchiha and Kakashi who's not even a Uchiha had awakened it.