Valley of the end, is there someone there? Is there something behind the waterfall? Then again this is just an idea don't know if anyone posted about this yet and if they did I apologize, to damn lazy to use the search bar.
Seriously you guys think that Kishi would waste one whole chapter on obito flashback and not let it be obito? For god sake the chapter is called obito uchiha, just wait for the next chapter it will explain everything, deal with it.