Originally Posted by
Rlinfamous
There's no denying Sasuke's in a really dark state of mind right now. However, that murderous look on Sasuke's face was before he met Itachi, and Sasuke is definitely showing a lot more of his old self in front of Itachi.
It IS still obvious how Sasuke's fallen and differs from Itachi, though... throughout the fight against Kabuto, Sasuke has taken the "shoot first, ask questions later or never" approach. It shows Sasuke's instability, irrationality, impulsiveness, and all the other factors that are leading Sasuke to seek violence and revenge. I don't see these things changing; I think the fight will highlight the differences between Sasuke and Itachi, and thus the differences in the paths they intend to walk. However, it's worth noting that in many ways Sasuke has the potential to be a much more heroic character than Itachi, in the same way Naruto is more heroic than Minato or Jiraiya. Naruto and Sasuke do not compromise their beliefs, they act on what they know to be right. Tobi may have corrupted Sasuke, but he did so by using Sasuke's own notions of justice, honor, and honesty against him. Once Sasuke wakes up, he will do what Itachi couldn't and truly take action against Tobi. By siding with Naruto and defeating Tobi, the root of all hatred, Sasuke might truly "purify" his clan's name, ending the cycle of hatred that has plagued the Uchiha for generations.