Naruto: Shippūden (2007)

S20E456 Itachi's Story - Light and Darkness: The Darkness of the Akatsuki

Itachi turns into a rogue ninja and aligns himself with the Akatsuki. Pain and Orochimaru greet him, introducing him as the former Leaf ANBU member responsible for the massacre of his whole clan. He is teamed up with a man named Juzo, and their initial mission takes them to the Land of Water, where they must carry out an assassination task.