"Assemble! Allied Shinobi Forces!" (集結! 忍連合軍!, Shūketsu! Shinobi Rengōgun!) is episode 256 of the Naruto: Shippūden anime.
Using his Earth Release: Ultralight-Weight Rock Technique, Ōnoki carries the Island Turtle all the way to Kumogakure. Having completed his S-rank mission, Naruto decides to check out the situation on the surface and to find out why Yamato has not returned. However, Aoba tells him that Yamato is still conducting surveillance, and is saved from prolonged inquiries when Killer B offers to help Naruto hone his mastery over the Nine-Tails Chakra Mode.
At the Mountains' Graveyard hideout, Kabuto asks Tobi to extract information from Yamato without killing him, citing that he needs Yamato alive to further his experiments on Zetsu and the White Zetsu Army, as the latter two contain Hashirama Senju's cells like Yamato does. Tobi is vexed that Orochimaru discovered that secret while also noticing that Kabuto has discovered the cells' weakness — snake venom.
Unbeknownst to Tobi, the Infiltration and Reconnaissance Party are above the underground hideout, where Tokuma Hyūga uses his Byakugan and discovers, to his shock, that the White Zetsu Army consists of 100,000 members. Relaying this information back to team captain Anko Mitarashi, she decides to notify the Allied Shinobi Forces. As a result, the shinobi of chūnin status or higher from each of the Five Great Shinobi Countries as well as samurai from the Land of Iron arrive at Kumogakure to be mobilise into several divisions, with each of them receiving a new headband signifying their alliance.
Chōza and Tenten are placed into the First Division led by Darui of Kumo, a unit composed of combatants who specialise in mid-range combat. The Second Division, consisting of short-range fighters such as Hinata, Neji, Karui, and Kurotsuchi, are led by Kitsuchi, a jōnin from Iwagakure. Guy, Lee, and Sakura are positioned in the Third Division, a unit comprising of short and mid-range combat specialists, with Kakashi as the unit commander, while Chōji, Shikamaru, and Temari are stationed in the Fourth Division, tasked with long-range battling, with Gaara serving as the captain of the Fourth Division as well as the commander-in-chief of the Allied Shinobi Forces.
As a contingency to counterattack any disadvantageous circumstances in battle, a special battalion known as the Fifth Division is formed, consisting of members who specialise in hiden, such as Ino, Kiba, and Shino, led by Mifune. Kankurō is assigned as captain of the Surprise Attack Division, comprised of shinobi who are adept at ambush tactics, including Sai and Omoi. An Intelligence Division is spearheaded by Inoichi, while C is placed under Ao's command in the Sensor Division; last but not least, the Logistical Support and Medical Division is established under Shizune's supervision. With all nine battalions being formed, the Allied Shinobi Forces are officially mobilised and ready for battle.
Back at the Mountains' Graveyard hideout, Yamato is secured to Hashirama's Artificial Body, where the cells of the First Hokage contained within his body are transplanted to the White Zetsu Army. To supplement their troops, Kabuto uses the Summoning: Impure World Reincarnation technique to call forth dead warfare aficionados to supplement their military force. Amongst the resurrected soldiers are the jinchūriki of the second, third, fourth, fifth, sixth and seventh tailed beasts; the Fourth Kazekage, the Third Raikage and the Second Tsuchikage, Hanzō of Amegakure, Chiyo of Sunagakure, Hizashi Hyūga, Dan Katō, Asuma Sarutobi, Kimimaro of the Kaguya clan, Gari, Zabuza Momochi, one of Kirigakure's Seven Ninja Swordsmen of the Mist, as well as his partner, Haku of the Ice Release; in addition, Deidara, Itachi, Sasori, Kakuzu, and Nagato, the former powerhouses of the Akatsuki. Satisfied with the infantry at their disposal, Kabuto and Tobi proclaim the Fourth Shinobi World War has officially begun.
- In his brief début, Hoheto Hyūga is depicted with black eyes. Also, Kitsuchi's hair is depicted as part of his forehead protector instead.