For Whose Sake?
Shana makes it to New York, and meets up with the rest of the gods of Earth. They agree to help Shana fight, and she then explains the plan to them. Yuji visited Misaki City and found Kazumi Yoshida and Eita Tanaka. He came back to convince Yoshida to join him in building the new universe. While Yoshida, Tanaka and Yuji walk around town, Yuji explains his what he intendes to do. After a while of explaining, Yoshida finally agrees to help him.
Aired 04/02/2012EP 17 - For Whose Sake?
Shakugan no Shana: Season III
Continuing from the events of the last series (Shakugan no Shana II), both Shana and Kazumi stand at their respective locations waiting for Yuji to meet with one of them, only to discover that Yuji has disappeared, with not even the slightest evidence of his existence left behind. All is not lost however, as the letters the two of them sent to him still give hope of Yuji's continued existence. As Shana and company search for answers on Yuji's whereabouts, they soon find the truth staring back at them when Yuji reappears in front of them as the leader of Bal Masqué. Left with little choice, Shana must now confront her most unlikely adversary on the battlefield in her toughest challenge yet.
(Source: Anime News Network)