Sorry for the late reply :/ Anyhow, yeah Sasuke has a final battle with Itachi and kills him (which was all part of Itachi’s plan), before the battle however Itachi explains how someone named Madara Uchiha also aided in the Uchiha Clans Massacre. At that point in time Tobi was believed to be Madara, but that is apparently not the case as Kabuto later on summons Madara via Impure World Resurrection >.> So, the new question of who Tobi really is has arose.