Shinobi War

The war began because of the return of Tobi—a former member of the Uchiha clan who sought to gain control over the tailed beasts and establish a new world order. Tobi announced the start of the war at the Five Kage Summit, declaring that he would use the seven tailed beasts under Akatsuki's control to fight the shinobi world.

Response: The Kage and General Mifune formed the Allied Shinobi Forces, pooling all their resources against Tobi and Kabuto.
The Battle against the Sound Four—The reincarnated Sound Four attempt to take revenge on the members of Sasuke Recovery Team who killed them years ago. Individually, the Sound Four are defeated, but using a Space-Time technique, their defeated bodies lure the souls of their targets into a trap.
The Battle against Obito—Obito forces the Juubi to take its true form: a giant tree capable of absorbing the chakra of anyone it touches. Due to dwindling numbers and a lack of time, the Alliance prepares to deliver a decisive blow.