Board Thread:Theories and Speculation/@comment-38812954-20191014152438/@comment-32685487-20191014213505

Kabuto repaired Sasuke's heart with Hashirama's DNA. Sasuke was going to get the Rinnegan anyway but I think Hagoromo knew that and he changed it so Sasuke could use his Left EMS with his Rinnegan at the same time giving it tomoe, the trade off is that he only has one Rinnegan.