The war of the Bijuu. The Fourth Shinobi World War as others called it. It is also known as the most dangerous war of all shinobi wars.
It all started with three Ame orphans, having a dream for absolute peace. Their group was once peaceful, but their views on this 'peace' got crooked and made them thirst for fear and power when one of them died saving a country. Thus, started the organization, Akatsuki, or The Red Dawn was created.
The next member was another crooked viewer of peace. Crushed between the rocks saving his teammate, everyone thought he was dead. Amazingly living without his other left half, retrieved by the legendary Uchiha and a plant-like man, he grew accustomed to his new body. Just in time to see his other teammate die because a lightning-based jutsu pierced her heart courtesy by his best friend. Knowing the reasons, he was okay, but seeing her die in front of him, by the hands of his best friend at most, and being hunted by the Iwa nin, he led to the conclusion that she was a candidate to hold a jinchuuriki, control her to destroy the opposing village, in other words, to be a spy for the Rock Village.
It led him to deduce that the whole world was power-hungry, and it was impossible to live in a peaceful life. His solutions were to kill all people, or control all the people. He chose the second option.
Devising a plan, he ended up creating the ultimate genjutsu ever; the Moon's Eye Plan. The plan was to direct his Sharingan to the moon, and cast an illusion to all people over the world who'd look towards After that, he would make the fake reality where everybody was friends, where everybody had their dream jobs, and everybody was good at their ninja capabilities/talents.
In other words, the fake reality.
The perfect life.
He knew anybody would like that. Hell, even he would like that.
But, together with the last remaining Ame orphans, knew that accomplishing this dream would need lots and lots of power and chakra, and theirs alone were nothing to control the technique.
They need powerful shinobi.
They need powerhouses. They needed chakra powerhouses.
They need the power of a bijuu.
Preferably, all nine bijuu, and revive a form once again of the creature that was sealed by the almost-mythical shinobi in the world in the moon- the Juubi, also known as the Ten Tails.
Akatsuki's view for peace spread, and required powerful missing-nins, bordering A- class to S-class ninjas of high caliber.
Along with Pein, a self-proclaimed god that was one of the Ame trio and once known as Nagato and best friend of Yahiko , Konan, another of the Ame trio and a paper-based jutsu user, and Uchiha Obito a.k. /Madara, once known as the ninja who was friendly towards everybody who awakened his sharingan saving his teammates, others also joined in.
Kakuzu the Immortal with Five Hearts. Almost inhuman looking when fighting, he has hearts masked by the elements, the pieces of porcelain lets him have all the elemental affinities. These hearts had also allowed him to live for decades for he has been alive at the time of the Shodaime Hokage, seeing he had once fought him. He can also repair himself with wire looking tendrils, and can extend this ability to his comrades to repair any damage.
Hidan the Immortal Jashinist. A fan of profanities, bloodshed and cutting/ripping, he has a crazed glee for fighting. His specialty was he can't be killed, and he can kill by using your own blood and performing a ritual for the so-called god Jashin. He cusses anybody who hated his 'god'.
Deidara the Mad Bomber. As his name suggests, his liking to explosions is world-known. His addiction was extended to the extent that he can make figurines of anything he wants that are made of clay created by the mouths on his hands. He calls this as, "unwei bakuhatsu no, un," translating to "Art is an explosion, yeah."
Sasori the Puppeteer of the Red Sands. To Suna, he is the grandson of the elder Chiyo, he made himself a puppet. Realizing he can be killed by anybody stronger than him, he changed into something repairable, his specialty; puppets. Storing his heart in a small device, only two had known that it was his weakness. He also makes his victims as his puppets, preferably the strong ones.
Hoshigaki Kisame the Tailless Bijuu. A shark-man look alike and a summoner of the sharks, he has powerful chakra reserves equal to a Bijuu. Former member of the Kiri no Shinobigatana Nananin Shu (The Seven Ninja Swordsmen of the Mist), he also uses the chakra-shaver sword that converts its 'food' to its user's chakra, the fearsome Samehada.
Uchiha Itachi the Sharingan Master. An Uchiha opposed to his clan like his best friend, he killed all the members of his clan in one night, except his brother. He is also famed for being merciful, polite and kind to his enemies and regrets killing in cold blood. He is a master of his clan bloodline, the Mangekyou, and also signed the Crow contract.
Zetsu the Black and White Artificial Human. Made by Madara Uchiha in one of his experiments, he looks like a man engulfed by a Venus flytrap. He has two halves; the White peacemaker, and the Black sadist. He was created by the cells of Hashirama Senju, the First Hokage. He is not easy to incapacitate for he can make real look-alike, copying everything about what it's replicating. He is the perfect spy, for he can travel underground at high speeds.
All of these people wear a black cloak with red clouds adorning it as their uniforms. Usually they have straw hats on to hide their faces, sometimes they do not. The similarity was that they travelled by pairs; and took orders from "Leader-sama". 'Leader-sama' was initially Pein, but later was replaced by Obito.
They succeeded in collecting the bijuus of Gaara; the Ichibi no Tanuki (Shukaku), from Sunagakure. Yugito Nii; the Nibi no Nekomata (Matatabi) from Kumogakure, the Yagura; tha Sanbi no Genbu (Isobu) from Kirigakure, Roshi; Yonbi no Saru(Son Goku) from Iwagakure, Han; the Gobi no Hokou (Kokuo) from Iwagakure, Utakata; the Ronbi no Namekuji (Saiken) from Kirigakure and Fuu; the Nanabi no Kabutomushi(Chomei) from Takigakure. These were the facts that they weren't weak; in fact all of them fought. Some of them fought the two Akatsuki members alone with their respective powers; which is impressive since they were technically fighting two S-class shinobi alone. Another was they were brainwashed, initially extracted but brought back to life, but since the life of a jinchuuriki was practically cursed of existence, other villages handed them readily to the Akatsuki without a challenge.
The exceptions were Kirabi; the Yondaime Raikage's adopted brother, an [awful] rapper and the Hachibi no Kyogyu(Gyuki) from Kumogakure, and Naruto Uzumaki-Namikaze; the son of the late Yondaime Hokage/Konoha no Kiroii Senko (Konoha's Yellow Flash)and the Akai Chishio no Habanero (Bloody Red Hot Habanero)plus the jinchuuriki of the Kyuubi no Yoko (Kurama) from Konohagakure.
Knowing that any resistance was futile, the Daimyos of the Great Shinobi Countries proposed a treaty between them. The Gokage Summit was the result, and the Five Shinobi alliance was created. Lead by the five Kages of each village, the alliance was divided into different aspects; the front, close combat ninjas; the second, the mid-range ninjas; the third, the medics and healer; the fourth, the strategists and communication networks.
The enemies were consisted of the monsters experimented by Madara Uchiha. All had monstrous looking forms, all had special abilities. They had to destroy their minds fully. This alone made the war difficult. Zetsu, one of his creations, made bodies that were undetectable combined with the restrained Yamato, and succeeded because it was made with Wood style cells. They unleashed an army of look-alikes and the shinobi alliance had difficulty judging who the true ally was and who was not.
This was defeated with the help of the Kyuubi jinchuuriki Naruto, who had the Kyuubi mode on. This technique allowed him to detect pure evil, and mind controlled shinobi.
Kabuto Yakushi, the temporary ally of Obito Uchiha, made things harder. Now, with the cells and techniques of Orochimaru the Snake Sannin and his former master, he used the technique Impure World Resurrection and resurrected the dead Akatsuki members, Momochi Zabuza the Demon of the Bloody Mist, Haku the last of the clan with Ice manipulation, Dan and Nawaki friends of Tsunade Senju, Asuma Sarutobi, and other missing-nins with remarkable techniques.
This was defeated by the resurrected Itachi Uchiha saved from the technique because of Shisui's eye in Naruto, with his brother Sasuke Uchiha. Fought a battle in a cave where Kabuto was found, the bespectacled-power hungry ninja was defeated with a Sharingan technique called Izanami. The mind-controlled shinobi outside the cave said their last farewell to their opponents and crumbled into dust.
After that, Madara unleashed the bodies of the former jinchuurikis along with their resealed bodies. All had chakra rods embedded into their bodies, controlled by the leader. All resumed their bijuu forms, but was later defeated when Naruto and Kirabi pulled out the rods, the latter with the help of Sage mode, and the other in his tailed form. Allies appeared once again, five out of nine were former traitors.
Orochimaru, Otokage and formerly one of the Densetsu no Sannin (The legendary Three), he came back following his all familiar wayward student Sasuke to achieve his dream, whatever-it-was. He helped resurrecting the former Hokages, the one of the four strongest ninjas in the world.
Sasuke Uchiha, former traitor of the Leaf. Betrayed his own village for power, being consumed by the darkness of revenge. Came back to help than destroy the world because of his brother's explanation, redeemed himself by tag-teaming with the Konoha Twelve, minus Neji Hyuuga.
Karin Uzumaki, last Uzumaki besides Naruto. Along with Suigetsu who wields the Kubikirirocho, and Juugo of the Curse Seal, they followed Sasuke to his decision for he was the leader of their self-proclaimed Team Taka (Hawk).
Hashirama Senju, resurrected by the Hebi Sannin, fought Madara Uchiha, a one-on-one,as they call it. Since the Uchiha would not budge until Hashirama was his opponent,they had no choice but to concede.
Tobirama Senju, along with his brother, ended being resurrected. He held up and did a jutsu weakening the Ten- Tails. Using his impressive control over water, he fought against the enemies.
Hiruzen Sarutobi, Sandaime Hokage. The same with his senseis, he used his abilities and a particular sealing that helped seal the Juubi along with his fellow Hokages.
Minato Namikaze, former student of Jiraiya the Gama Sannin showed up also, doing so what his fellow hokages were doing. In Kyuubi mode, he offered his last Ying chakra to his son in the end, as his parting gift.
His son thanked him and with the reunited with the former Team Seven and remaining members of the Konoha Twelve. Sasuke Uchiha, Sakura Haruno, and Naruto Uzumaki- Namikaze, also dubbed as the second coming of the Legendary Sannin that were ironically the ones that taught them, made their presences known in the battlefield.
Their personal summons were introduced.
Gamakichi, son of Chief Toad Boss Summon Gamabunta, for the Nine Tails jinchuuriki.
Aoda, son of Chief Snake Summon Manda, for the Eternal Mangekyou sharingan user.
Katsuyu, Chief Slug Summon and Healer, for the Head Medic kunoichi.
They fought the Juubi with the help of the summons and the combined efforts of all shinobi.
The war had ended eventually.
But it didn't end without a heavy price.