As you may know kishi has givin us everything we can ask for as fans of the series. And what I mean by that is we got to experience all these legendary ninjas fight, we got to se the Kages all the edo tensei and a few other legends show off there talent.. Now wat does that have to do withe mystery guy .. Think hard there is one legend out there that even itachi can't live up to and we never got to see this person fight.. Who's this person?? Shisui uchiha the teleporter..
I know what ur saying... No he's dead..
But his body was never found all they found was his suicide note..
I also know hes blind,
this is where it gets tricky.. From what we've seen with itachi And sasuke their family carry the same MS techs ametarasu etc... So would it be too out of the ordinary to believe shisui is obitos brother.. I believe their eyes both give them the ability to teleport.. And u see where I'm going with this shisui will take his brothers eyes and have EMS, still doesn't seem that helpful against madara but when u consider shisui is probably the 2nd strongest Uchiha we don't know what he brings to the table.. Itachi is his underling and he has things like the totsuka blade and the mirror that repels
. imagine what shisui could do.. And there's enuff background with shisui and itachi that it makes sense he would come to sasukes aid.. What do u think