I think it's Shisui but what is confusing me is why Oro said to Sasuke "you're still a child???
It should be someone from the time of the massacre and not Izuna. That would be a different generation. Sasuke wants to find out why Itachi protected the village and what a shinobi is. That part is the most exciting part of the whole story, by far.
Idk now that shisui doesn't have his eyes.......so it can't be him.
Maybe some random uchiha