Kurama

- A young Kurama. - Yin and Yang-Kurama. - Minato and Naruto's Tailed Beast Mode. 1/3 Kurama is a red-orange coloured kitsune with black fur around its red eyes that stretch up to its ears, and nine long swiping tails. It also has an upper-body structure of a human, complete with opposable thumbs on its clawed hands. During the last remaining days of Hagoromo, Kurama in its youth was much smaller in size, yet still towering over an adult, with leaner and softer while less-defined in shape with a rounder face, akin to a fox cub. Over time, Kurama's size grew to roughly equaling the Hokage Rock, and Gamabunta, the largest of the Mount Myōboku's toads, was only the size of Kurama's torso. Its pupil alone was bigger than a tall human. When Minato separated Kurama's Yin chakra and Yang chakra, it was split into two entities, both of which were shrunken more than half its original size, yet still roughly the size of other massive tailed beasts. While the two were basically identical to the other, Yang-Kurama retained its original colouring while Yin-Kurama was darker coloured. While manifesting its Nine-Tails Chakra Mode, the fox's entire body took on a transparent golden colour, its whiskers were much thicker, and black circular markings appeared on its shoulders, stomach, as well as the front and back of its paws. Black lines also ran the length of its spine, arms, legs and tails. Additionally, while Naruto is in Sage Mode, Kurama gained similar thick dark patches circling around its eyes. Upon gaining Naruto's Six Paths Chakra, Kurama's Tailed Beast Mode avatar grew to tremendous proportions, roughly the same size as Sasuke Uchiha's Six Paths Complete Body — Susanoo, with its tails becoming bushier. After both halves of Kurama were reunited, the fox grew even larger than ever before, to the point it was towering over a stump of a God Tree. Three years after its demise from over-usage of the Baryon Mode, Kurama reformed as cub like it did when first created by Hagoromo, albeit much smaller, roughly the size of a large pet dog, with very long tails.

Kurama and the tailed beasts first came into being in the waning days of Hagoromo Ōtsutsuki, who used his Creation of All Things Technique to divide the Ten-Tails' chakra into nine separate bodies and give them each a name. Sometime after being created, the Sage explained to the young tailed beasts that a link existed between them despite their separation. He also foretold of a day when they would be brought together again—though not as they were—and that at that time someone would emerge to show them what true power is. In the anime, before his death, Hagoromo sent Kurama to live in a temple built for the purpose of protecting it in a forest region with mountains that would later become part of the Land of Fire. Over time, Kurama gained a fearsome reputation as a natural disaster that can desolate areas where the darkest aspects of human nature collect and fester. During the time of the founding of the shinobi villages, the Gold and Silver Brothers of Kumogakure were assigned to capture Kurama, but they were both swallowed whole by the fox. However, the two brothers survived and gained some of its power by eating the flesh of its stomach for two weeks, forcing Kurama to regurgitate them. After Madara Uchiha's defection from Konohagakure, he found Kurama and used his Sharingan to control it, forcing the fox to help him fight against Hashirama Senju, the First Hokage. The epic battle left a colossal scar in the earth that would come to be called the Valley of the End. After his victory over Madara, Hashirama's wife, Mito Uzumaki, sealed the fox within herself, becoming its first jinchūriki. Over the period of time that included the First and Second Shinobi World Wars, Mito kept Kurama at bay except when the seal nearly broke when she was going through childbirth. Towards the final years of Mito's life, it was decided that a new jinchūriki would have to be found, and that was another member of her clan, Kushina Uzumaki. Although Kushina was terrified when she learned of it, Mito comforted her young successor by telling her that by filling herself with love, Kushina would overcome the fox's hatred. This was shown years later that despite Kurama's constant attempts to destroy her hope for happiness as its jinchūriki and coerce her to break the seal, Kushina's love for Minato Namikaze and his love for her were proven to be strong enough to contain the fox. Soon after the end of the Third Shinobi World War, the Third Hokage made special arrangements for Minato to ensure that Kurama would remain sealed inside Kushina while she gave birth to Naruto on the night of October 10. However, despite keeping the childbirth a secret, a masked man called Tobi tracked down their location, killed their escorts, and held Naruto hostage, forcing Minato to quickly rescue him and teleport him to safety. Right after Tobi captured Kushina, he extracted and seized control of Kurama and tried to have the fox kill its barely surviving jinchūriki, but Minato made it in time to save her. Soon afterwards, the masked man summoned Kurama into Konoha and ordered it to destroy the village. While Kurama was rampaging in the village, Minato fought against Tobi and soon managed to place a Contract Seal on him, which freed the fox from his control. Despite that, Kurama still harboured resentment against Konoha for sealing it away and continued decimating the shinobi forces that tried to repel it. As it prepared a Tailed Beast Ball, Minato summoned Gamabunta on top of the fox and quickly teleported it to Kushina and Naruto's location, letting its Tailed Beast Ball detonate away from the village. Already dying from the extraction, Kushina used her remaining strength to restrain Kurama, planning to seal the fox back inside her so it would die with her. However, knowing that Kurama would revive without a host and how great a threat Tobi was, Minato instead came up with a plan to give his son the means to combat the masked man in the future. Because it was impossible for Minato to seal Kurama entirely on his own, he first used the Dead Demon Consuming Seal to separate and seal the fox's Yin half within himself and then prepared the Eight Trigrams Seal to imprison the Yang half within Naruto. Realising what they were planning, Kurama attempted to kill Naruto, but both of the parents used themselves as shields and completed the sealing. Although greatly frustrated of being sealed again, Kurama decided to wait for the time when it could influence Naruto to use its power to break the seal. Throughout the years, Kurama weakened the seal through the cracks of its formation by constantly sending out small portions of its chakra, which had positive side-effects on Naruto, such as amplifying his naturally large chakra reserves and healing ability, being able to heal from minor wounds within seconds to major injuries within a day. In the anime, it was revealed that Kurama had left behind large amounts of its chakra during the attack. Kazuma, a former member of the Twelve Guardian Ninja, collected and sealed the chakra within his son, Sora, hoping to make use of its power for his own agenda.