Fourth Shinobi World War

The is a conflict between the Allied Shinobi Forces and Madara Uchiha. It's beginning was declared by Madara Uchiha when the five Kage and the leader of the Land of Iron unanimously refused to give him the Eight-Tailed Giant Ox and the Nine-Tailed Demon Fox for his Eye of the Moon Plan. Madara then stated that he would use the seven tailed beasts already captured by the Akatsuki in combating the ninja world. After this the Fifth Kazekage, the Fifth Mizukage, the Fourth Raikage, the Third Tsuchikage, and General Mifune agreed to form a Shinobi Alliance, pooling their resources against Madara. Later the daimyō of the Five Great Shinobi Countries and the Fifth Hokage joined the alliance while Kabuto Yakushi formed an alliance with Madara.

Preparations for War
Both sides began by gathering their strength and collecting information about the other side in preparation for the upcoming hostilities. Kisame gathered intelligence on Kumogakure's military strength and on Killer Bee while traveling with him everywhere hidden inside Samehada. The team of Anko Mitarashi tracks Kabuto Yakushi, which led them to Madara Uchiha's lair. Other Shinobi Alliance teams have fanned out to collect other information about Akatsuki and their hideouts.

Kabuto has formed an alliance with Madara, showcasing his use of the Summoning: Impure World Resurrection technique, increasing the forces of Akatsuki with the resurrection of dead members of the organization. The Five Kage have decided to hide the two remaining jinchūriki, Naruto and Killer Bee on an island in the Land of Lightning. Hiding Killer Bee and Naruto had the unintended result of allowing Naruto to learn to control the Nine-Tailed Demon Fox's chakra, much like the way Killer Bee has of the Eight-Tailed Giant Ox. Having been successful in his training, Naruto has exhibited increased speed and strength when utilizing the controlled chakra of the Nine Tails but lacks the same finesse that Killer Bee had exhibited in utilizing the Eight Tails', crashing into the wall and crushing rocks whenever he uses the Nine Tails chakra.

Despite being captured in the end and committing suicide to keep the information he held secret, Kisame was able to finish Akatsuki's preparations for the War by sending a summon shark with a scroll to his comrades, divulging the proximate location of the Turtle Island. With the battle between the two forces seems to be on the horizon, Madara had dispatched Kabuto to retrieve the Nine-Tails and Eight-Tails with the revived Deidara but was stopped by Ōnoki, Akatsuchi and Kurotsuchi who was going to reinforce the forces on the Island Turtle. But Kabuto still made it out with Yamato, further adding to the intelligence sources that Akatsuki has on the Shinobi Alliance and also intending on strengthening the Zetsus with Yamato's powers.

Both the Allied Shinobi Forces and Akatsuki have amassed considerable forces for this war, 80,000 shinobi and samurai total make up the Alliance and 100,000 Zetsu clones and at least 35 warriors of note revived by Kabuto make up Madara's army.

Allied Shinobi Forces
The Allied Shinobi Forces created by the Five Great Nations and the Samurai of the Land of Iron consists of five main divisions, with Gaara of the Sand as the Regimental Commander. The 1st Division consists of mid range fighters and is led by Darui. The 2nd Division is made up of close range fighters and is led by Kitsuchi. The 3rd Division is under the command of Kakashi Hatake, and features both close and midrange fighters. The 4th Division contains only long range fighters under the control of Gaara. Shikamaru is Gaara's right hand man and proxy commander of the Fourth Division as well. Finally, the 5th division was created for the purpose of special operations, and features ninjas with unique skills. Mifune is the leader of these special operatives. There is also four special company formed for the war. The Logistical Support and Medical Division led by Shizune comprises of medical ninja, the Surprise Attack Division led by Kankurō, has the task to ambush the enemy forces. The third is the Sensor Division with Ao as captain, and finally the Intelligence Division headed by Inoichi Yamanaka is intended to gather information and relay it to Gaara for strategy's sake.

Akatsuki
Akatsuki, run by Madara Uchiha, has evolved since its first introduction. Its second in command is Kabuto Yakushi, and operate out of a base to the north. There are four living members: Madara, Kabuto, Sasuke Uchiha, and Zetsu. However, Zetsu has 100,000 clones ready for battle, which were somehow created using Hashirama Senju's power. Kabuto also has revived quite a large number of once-famous powerful shinobi.

Allied Shinobi Forces
Analyzing their own and their enemy's location, they have decided that Akatsuki will send a small fraction of their army by sea from the Mountains' Graveyard (Akatsuki's hideout) to Kumogakure, and that most of the army will travel by land. This would require the army to move through both the Land of Frost and the Land of Hot Water. An immediate evacuation notice was sent to both countries, and they will most likely evacuate to the south, in the Land of Fire. The First Division, which is the mid-range battle division, is stationed in the northern part of the Land of Lightning, in order to prevent the Akatsuki from using the small gulf to infiltrate the area from Mountain's Grave. The Second Division, or short-range battle division, is on the border of the Land of Lightning and the Land of Frost, sealing a northerly path into the Land of Lightning. The Third Division, or the short- to mid-range battle division, was advancing fast through the middle of the Land of Frost, but was called into the northern part of the Land of Hot Springs to aid the Surprise Attack Division. The Fourth Division, the long-range battle division, is on the border of the Land of Lightning and the Land of Frost, sealing a southerly path into the Land of Lightning. Mifune's Fifth Division, the special battle division, is aligned in a large arc from the north part of the Land of Frost, through the middle of the border between the Land of Frost and the Land of Lightning, all the way to just south of the First Division, in order to aid any of the divisions that need immediate response, and to finish the seal on the Land of Frost and the Land of Lightning's border.

Akatsuki
Much less is known about the Akatsuki strategy, but it is evident that their primary goal still remains the acquisition of the surviving jinchūriki. From the small amount of information that has been divulged; Kabuto will maintain direct manipulation of the movements of the resurrected individuals until they have reached the appointed destination, with the intention of eradicating their personalities when the actual conflict begins to turn them into mindless implements of death, while still manipulating any emotional response they could potentially illicit to full advantage, in the hopes of inflicting further damage. During the course of this approach, a small Surprise Attack and Diversion Platoon (comprised of Sasori, Deidara, Chūkichi and Shin) will attack from the air, utilizing bombs and traps to disperse the enemy. However, realizing that the movement of their entire army in such a large and apparent fashion would be far too conspicuous, the decision has been undertaken to translocate the 100,000 Zetsu clones beneath the ground, in order to thoroughly conceal the approach of the main contingent of their forces.

Battles
As both sides prepared for the war, Akatsuki continued its standard methods of capturing the jinchūriki.

Capturing the Eight-Tails

 * Location: Sabu's Home
 * Combatants
 * Akatsuki: Kisame Hoshigaki, Zetsu
 * Enka Ninja: Killer Bee, Sabu, A, C, Darui
 * Outcome: Kisame able to infiltrate the Allied Forces.

After tricking Taka into believing they had captured him, Killer Bee sought out the enka ninja Sabu to learn from him. Kisame Hoshigaki tracked him down with Samehada and the battle ensued. When the Fourth Raikage and his two C|bodyguards arrived, Kisame was thought to have been killed. This was however a unique clone created by Zetsu and the real Kisame was hidden inside Samehada, which Bee had claimed, to gather information on what the Allied Forces were going to do with the shinobi.

Battle on the Island Turtle

 * Location: Island Turtle
 * Combatants
 * Akatsuki: Kisame Hoshigaki
 * Allied Shinobi Forces: Aoba Yamashiro, Killer Bee, Might Guy, Motoi, Naruto Uzumaki, Yamato
 * Outcome: Kisame killed, Akatsuki finding the location of the jinchūriki, and gaining intelligence on the movements of the Allied Shinobi Forces. Akatsuki strategic victory, Allied Shinobi Forces tactical victory.

By hiding in Samehada, Kisame was able to not only gather information on the Allied Forces base of operations but the location of the jinchūriki. Traveling with Bee to the Island Turtle he remained unnoticed by everyone until Naruto's new power allowed him to sense Kisame in the sword. As Kisame fled, he was encountered his old foe Might Guy and the two squared off in a final battle. Using his Daytime Tiger, Guy managed to capture Kisame but before he could reveal any information he killed himself with a shark summon.

With Kisame dead, the Allied Forces attempted to figure out what Kisame had managed to learn about them through the scroll he left behind. When the scroll opened, the trap activated, trapping everyone in a Water Prison Technique and another shark to take the information scroll back to Madara.

Battle for the Rinnegan

 * Location: Amegakure
 * Combatants
 * Akatsuki: Madara Uchiha
 * Amegakure: Konan
 * Outcome: Madara obtains the Rinnegan, Amegakure loses its village head, Konan. Akatsuki victory.

Madara Uchiha confronted Konan within Amegakure in order to obtain the Rinnegan from Nagato's corpse. Having prepared to fight Madara, Konan had integrated over 600 billion exploding tags into her paper jutsu, knowing that Madara can only stay intangible for five minutes and set off enough explosions to last ten minutes. With her chakra depleted, Madara revealed that he survived the explosions using the power of Izanagi sacrificing his left Sharingan. He then used a genjutsu to get Nagato's location from her, killing her in the process, Madara claimed Nagato's body and took the Rinnegan for his own.

Second Battle on the Island Turtle

 * Location: Island Turtle
 * Combatants
 * Akatsuki: Deidara, Kabuto Yakushi, Manda II
 * Allied Shinobi Forces: Akatsuchi, Aoba Yamashiro, Kurotsuchi, Motoi, Ōnoki, Yamato
 * Outcome: Yamato captured. Akatsuki victory.

With the jinchūriki's location known, Kabuto volunteered to capture the jinchūriki. Kabuto chose the resurrected Deidara to accompany him and to set out to find the island by air. The Third Tsuchikage and his guards, being notified that the island turtle's location has been compromised, flew to the island to defend it from potential attack. The two parties intercepted each other en route and the Tsuchikage and Akatsuchi opted to fight Deidara while Kurotsuchi pursed Kabuto to the turtle.

The island turtle, which had moved from the previous location was quickly found by Manda II. The giant serpent flipped the entire turtle over stopping it's movement. Yamato, Motoi and Aoba left the inner part of the turtle shell and encountered Kabuto just as he and Kurostuchi arrived. Kabuto avoided their combined efforts by revealing that he had turned his body into a giant white snake, similar to Orochimaru. Figuring that the jinchūriki were too protected to be captured alone, he instead captured Yamato, the user of the First Hokage's Wood Release and returned to Mountains' Graveyard.

Battle of the Surprise Attack Divisions

 * Location: Land of Hot Water
 * Combatants
 * Akatsuki: Surprise Attack and Diversion Platoon
 * Allied Shinobi Forces: Surprise Attack Division, Infiltration and Reconnaissance Party (third team, except Anko)
 * Outcome: Deidara is captured. Shin and Sasori return to the afterlife. Chūkichi flees. Anko Mitarashi is imprisoned. Muta Aburame is killed. Allied Shinobi Forces victory.

Both Surprise Attack squads meet coincidentally in the Land of Hot Water, and they engage in battle. Akatsuki makes the first move, but the Allied Shinobi Force's numbers and strategy of luring Akatsuki into their terrain give them the upper hand. The Allies were able to use their emotions to put them at their highest capacity, including a calm Omoi, a furious Sai, and a determined Kankurō.

Allied Force's Ambush

 * Location: Land of Hot Water
 * Combatants
 * Akatsuki: Haku, Pakura, Gari, the previous Seven Ninja Swordsmen of the Mist
 * Allied Shinobi Forces: Surprise Attack Division, Third Division
 * Outcome: Ongoing. Tajiki, dozens of Allied Shinobi killed or wounded. Zabuza and Haku immobilized.

The Surprise Attack Division launched an ambush on the Akatsuki shinobi, which easily survived the attack. They then notified the Third Division with a flare, who quickly arrived. Zabuza Momochi then pleaded with Kakashi Hatake to kill them, then Kabuto Yakushi's jutsu forced the battle to begin. Zabuza concealed the Akatsuki's movements with his Hidden Mist Technique.Pakura used Scorch Release: Extremely Steaming Murder to kill at least two ninjas, and Tajiki was killed by Gari with Explosion Release: Landmine Fist. Sakura Haruno, being a medical ninja, helped heal the injured. Pakura and Gari then summoned the rest of the previous Seven Ninja Swordsmen of the Mist. The new swordsmen then attacked, using their superior swordsmanship to kill at least a dozen more allied shinobi. Kakashi developed a plan involving Ensui Nara, Santa Yamanaka and Maki to trap Zabuza. However, Haku once more saved Zabuza, holding Kakashi in place, which Zabuza tried to exploit by attempting to slash through both of them. Kakashi was slashed yet survived and immediately countered, allowing Maki to immobilize the recovering Haku and Zabuza, stopping the Hidden Mist Technique.

Assault on the White Zetsu Army

 * Location: Border of the Land of Frost and the Land of Lightning
 * Combatants
 * Akatsuki: White Zetsu Army
 * Allied Shinobi Forces: Second Division, westerly section of the Fifth Division
 * Outcome: Ongoing.

Kitsuchi and Kurotsuchi used Earth Release: Opening Earth Rising Excavation to unearth the moving Zetsu army, and then the divisions immediately attacked. The opening shots seemed to have destroyed a significant quantity of the Zetsu Clones before they had a chance to mount any form of counter-attack. However, as a seemingly unending number of durable clones continued to emerge, the conflict quickly descended into one of attrition, tiring much of the Allied Shinobi Forces and allowing thousands of the clones to proceed without hindrance underground.

Trivia

 * Itachi Uchiha prevented an earlier potential outbreak of a Fourth Ninja War by carrying out the Uchiha clan massacre.
 * A Fourth Ninja War was also declared by Hiruko in the third Naruto Shippūden Movie, and would have pushed through if not for the efforts of select Konoha shinobi.