Re: Uchiha Madara
At this point nobody knows and nothing is mentioned in the manga or anime so all we can do is speculate. As far as we know Kakashi does say they were two shinobi's in a never ending battle and the river flowing from the water is a representation of this "never ending" battle those two shinobi's had.
“Pirates are evil? The Marines are righteous? These terms have always changed throughout the course of history! Kids who have never seen peace and kids who have never seen war have different values! Those who stand at the top determine what's wrong and what's right! This very place is neutral ground! Justice will prevail, you say? But of course it will! Whoever wins this war becomes justice!”
― Donquixote Doflamingo