"The Third Power" (第三勢力, Daisan Seiryoku, Viz: A Third Force) is chapter 592 of the original Naruto manga.
Reflecting on Itachi's last words, Sasuke is tormented with questions about important aspects of a shinobi's life; including his clan, his friends and about his own existence. While deep in thought, the ceiling of the cave breaks open, but Sasuke manages to dodge the falling debris and Suigetsu appears, along with Jūgo, stating that they had finally found Sasuke. Meanwhile on the battlefield, the five Kage are still amazed to find Madara still intact even after the Impure World Reincarnation was released. Madara exclaims that after fighting him, they might have realised he was not the type of shinobi to be under someone else's control. He also states that anyone that had seen his perfect form of his Susanoo had to die but laments that it would be a disgrace and defeatist to manifest it once again. Elsewhere, Naruto, Kakashi, Guy, and Killer B are still fighting Tobi and the Demonic Statue of the Outer Path with Naruto provoking Tobi to take off his mask despite Kakashi's warnings not to irate the enemy. Seemingly resigned to his actions, Tobi summons the Benihisago and the Kohaku no Jōhei, and while remembering the fragments of the chakra he had collected from the Eight and Nine-Tails laments that he wanted to revive the Ten-Tails in perfect condition but even at a fragments of its power, it was still the same. Back at Kabuto's location, Jūgo realises that Anko Mitarashi is still alive and alerts Sasuke to the fact that Madara was still in the living world, shocking Sasuke. As Sasuke questions them why they were still following him, Suigetsu tells him that they had found something interesting and hands Sasuke the scroll which they found at one of Orochimaru's hideouts. Rendered speechless for a moment by the content, Sasuke says that he is willing to meet with Orochimaru which shocked Suigetsu and Jūgo but Sasuke noted that Orochimaru was not one to die so easily even if he was killed. Standing up, Sasuke states that he was going to meet "the ones who know everything".
When Sasuke questioned what are shinobi, he envisioned Shikamaru, Chōji, Ino, Kiba and Shino in their part II appearances, despite never seeing them since leaving Konoha in part I.