When does Naruto join the war?

Naruto and Killer B make it to the battlefield after getting clearance from the Hokage and the Raikage. Upon reaching the battlefield, they are ambushed by members of the WhiteZetsuArmy in disguise. With the help of his newfound power and abilities, Naruto manages to clear out of there with no difficulty. Naruto then sends his Shadow Clones to several battlefronts where the battle was raging.

Meanwhile, at the Logistical Support and Medical Division, members of the White Zetsu Army had infiltrated disguised as injured shinobi. Members of the Allied Shinobi Force were in a stand-still situation. No one was allowed in the central tent where Sakura and Shizune were conducting their autopsy. They were researching in order to gather more intel on the enemy to pass on to the HQ.

Elsewhere on a different battlefield, the Fourth Division, consisting of Gaara and Oniki, were holding their ground against Second Tsuchikage, Second Mizukage, Fourth Kazekage, and Third Raikage. Gaara attacks the previous Kages with a huge torrent of sand but is countered by his father, the Fourth Kazekage, using his GoldDust. Gaara successfully captures 3 of the 4 Kages with his sand arms but his father manages to slip through his fingers. Rasa wonders and asks his son where the One-Tailed Beast resided within him. While preparing for his next attack, Garra informs his father that he is no longer the Jinchiriki, the monster that his father turned him into.

1. Naruto showcases his newfound power, known as Kurama Chakra Mode. He displays versatile use of his signature techniques, Rasengan and Rasenshuriken, and their variations. Naruto sets out several of his Shadow Clones to different battle fronts.

2. Onoki and Gaara confront their predecessors on the battlefield. Gaara displays his skills on the battlefield by successfully capturing 3 out of 4 Kages with his sand arms. He then tells Rasa how much he has changed and that he was no longer the monster that his father created.

Q. Why did the war start in Naruto?

A. Obito Uchiha, impersonating Madara Uchiha at the time, declared war against the shinobi world. He declared war in the Five Kage Summit when the Five Kages refused to hand over the Eight-Tails and Nine-Tails Jinchuriki to him.

Q. How long was the 4th ninja war?

A. The Fourth Great Ninja War lasted for a total of 3 days. It started on 8th October and ended on 10th October. With the obliteration of Akatsuki and Ten-Tails getting sealed, the Allied Shinobi Forces emerged victorious from the war.