Zetsu, the Akatsuki's spy/Half man half plant/ cannibal. You can see him come out of the walls when Sasuke is fighting Itachi's clone, and winning, until 'Itachi' points over to the chair I called Ita-kuns throne, and there sat the REAL Itachi.
SPOILER-
After Sasuke kills Itachi, 'Tobi' who is actually Madara tells him why Itachi killed the Uchiha clan, even though he was in on it. Sasuke was outraged, and actually cried. He went and tried to destroy The leaf, and Joined Madara in the Akatsuki along with team Hebi.(Karin, Jugo, and Suijetsu(LOL I failed spelling x-x))
~Dosu Uchiha
episode 134-138 is the final battle between sasuke and itachi
it was episode 137 when the fight started and ended at episode 138 but was explained in episodes 135 and 136 (in Naruto Shippuden)
chapter 367
They fight episode 135-138
Yes madara said so himself on manga 463 page 10
yes [warning spoiler sasuke kills itachi in shippuden]
at episode 136 shippuden sasuke first got in the fight with itachi. by episode 139 the fight was over. he won because his chakra overbeat itachi's. itachi used susano'o and ameterasu but sasuke summoned orochimaru. In the end. (Spoiler) Sasuke later learns the uchiha secret. He learns his brother wants to die in the fight/.
yes i did not want to give spoilers but sasuke fights itachi and takes sasukes left eye and sasuke takes itachis right eye they keep fighting so finally sasuke kills itachi and does the head poke thing before he dies
episode 134-138 is the final battle between sasuke and itachi
they find each other in shippuden and yes they do have a fight to the death
This fight between Danzo and Sasuke happens in Naruto Shippuden Episode 209: Danzo's Right Arm. More information about Itachi comes out in this episode as well.
He appears because it was time for Sasuke to fulfill his dream: Kill Itachi. He wants to kill Itachi because 12 years ago, Itachi killed the entire Uchiha family, and because Sasuke is part of the Uchiha family, and also Itachi's brother, he found a great chance to avenge his family. By the time he killed Itachi, he was told all the true secrets which he should have known befor he killed Itachi. _______________________________________________________________________ Basic Answer: He appeared because he wanted to fight Sasuke and let Sasuke do what he wanted to do for a long time.
it was episode 137 when the fight started and ended at episode 138 but was explained in episodes 135 and 136 (in Naruto Shippuden)
I believe he appeared in episode 113, 114, 121, 123-126 and in his fight with sasuke
Well its going to be the latest shippuden episode were they have a really big fight, i belive then sasuke will kill itachi
Yes by Itachi dying in the hand of Sasuke it awaken the Mankeyo Sharingan.
Itachi did not fight with Guy instead he fought Kakashi somewhere in 80+.