Reinforcements Arrive

is episode 321 of the Naruto: Shippūden anime.

Summary
As the White Zetsu Army clones continue to wreak havoc on all the battlefields, the Allied Shinobi Forces struggle to find a way to cope with the situation until Naruto arrives. Elsewhere, the Daimyō Protection Squad continue their battle with Black Zetsu. Eventually Naruto's shadow clones arrive on all the battlefields, and slowly but surely the Alliance retakes the upper-hand on the battlefield. As reports dome into HQ of Naruto's part in turning the tides of the war back in their favour, Tsunade smugly gestures to A who solemnly dismisses her. The Sensor Division is asked to check on Madara's status and Ao reveals that he had started to move with a team of reincarnated jinchūriki. Meanwhile where the remainder of the Fourth Division is located, Kabuto Yakushi puts his trump card into play and uses Mū to summon another to the battlefield. With the coffin blown off upon summoning and Mū just nearly dodging the blow, a sensor amongst the Alliance alerts them to the appearance of new adversaries. Those present are shock to see, however, Mū atop the rock, which leads Ōnoki to realise that the Second had split in two before being sealed. As the second person is revealed to the puzzled Alliance, Ōnoki informs them that Madara Uchiha now stood before them. Believing the masked man to have finally entered the fray directly, Gaara turns their attention to Madara's eyes noting that he had been reincarnated. Throwing them into further confusion, Temari reminds them that the person who they thought was Madara had been spotted elsewhere with an army of his own, leading them all to wonder who that masked man truly was.