Kakashi's Anbu Arc: The Shinobi That Lives in the Darkness

The is the seventh filler arc from Part II of the series and spans from episode 349 onwards. The arc focuses on Kakashi Hatake's ANBU background, taking place after the battle at the Kannabi Bridge, losing his closest friend Obito Uchiha, and later taking Rin Nohara's life with his own hands.

This arc begins with the Ino-Shika-Cho former team being sent out to complete an Iwagakure treaty mission. A large battle almost breaks out until the Fourth Kazekage arrives and fixes the ordeal. They talk about the treaty to Onoki (The Third Tsuchikage) and Iwagakure's Council about the future. Meanwhile we skip over to Kakashi who is still extremely hurt about killing Rin Nohara and her death causing him to become almost completely withdrawn from outside things. Meeting with Danzo, Hiruzen and the Konoha Council, they chat about Konohagakure's future and how the Third Hokage will soon retire from his position as Hokage so that a new Hokage can blossom into the village.