Kurama


 * Name: Nine-tailed Demon Fox (九尾の妖狐 Kyūbi no Yōkō)
 * Creature type: Fox
 * Host: Naruto Uzumaki
 * Unique Traits: Near limitless chakra, massive strength
 * Status: Active, sealed in host.

The nine-tailed demon fox is a truly powerful beast; a single swipe of one of its nine tails can raise tsunamis and flatten mountains. It is said that the demon fox is an age old disaster which can appear from nowhere and goes where human malice collects and festers. After the demon fox attacked Konohagakure, the Fourth Hokage sealed it into the newborn Naruto by using the Dead Demon Consuming Seal, sacrificing his own life to do so.

Background
Little is known about the demon fox, other than it was a beast of pure malice, and appeared as a natural disaster in areas where human malice festers. The demon fox's only known exploit was its attack on Konoha, where as it decimated all the ninja that came at it, only to be defeated by Minato Namikaze, and Gamabunta. At an unknown time before attacking Konoha, the demon fox met with the founder of the Uchiha clan, Madara Uchiha who's Mangekyo Sharingan to control the demon fox, possible as Jiraiya would later say that he believed the demon fox attacked Konoha. Ever since, the demon fox has a special loathing for the Sharingan and those who uses it, even remarking Sasuke Uchiha's chakra was more sinister than its own, because it reminded him of Madara.

Personality
The demon fox is a beast of almost complete malevolence. It is intelligent, and has a scathing and sadistic personality. However, it has a sense of honor, and seems to possess a respect for Naruto and the Fourth Hokage. Additionally, it has a distinct sense of pride and became rather angry and scornful at Naruto when he rejected its chakra in Part II, though this might have merely been anger over missing an opportunity to partially usurp control over Naruto's body. The fox relishes the thought of killing Naruto but knows it has to help as long it's sealed within him or it will die. As it was being supressed by Sasuke Uchiha, the fox warned Sasuke to not kill Naruto, he'd only end up regretting it if he did. What exactly he'll regret is currently unknown.

Activity inside Naruto
As the demon fox's host, Naruto has accelerated healing, almost unrivaled stamina, and access to the demon fox's immense amount of chakra. The near-limitless chakra allows Naruto to perform his signature jutsu, Shadow Clone Technique, seemingly without limit. He is even able to summon Gamabunta the "Toad Boss", a normally Kage-level feat requiring an amount of chakra proportionate to the size of the summoned creature.

Naruto typically accesses this prodigious supply of chakra from the demon fox during extreme emotional states or life-threatening situations. When he first accessed it, the demon fox's innate rage took over Naruto's mind, causing him to strike out at whatever was near him at the time. Afterwards, Naruto learned to exercise more control over the chakra, and he can now retain his mental state when drawing upon small amounts of the demon fox's chakra. After Jiraiya's training, Naruto learns to summon a small degree of the demon fox's power at will. To do this, Naruto travels into his own mind (depicted as a sewer) and demands that the demon fox give him its chakra. He calls it "rent". The demon fox seems to comply simply because it is amused by Naruto's bravery, as well its own vested interest in Naruto's continued survival.

The Third Hokage and Kakashi Hatake allude that if Naruto loses all control of the demon fox's chakra, the seal will break and the demon fox will be freed. Though the seal is unlikely to break on its own, the chances of it happening increase as Naruto draws upon the fox's chakra. After Naruto trained with Jiraiya, and Jiraiya inadvertently released the four-tailed transformation, Jiraiya mentions that the seal may be becoming weaker over time. This is evident in Naruto's transformations, which occur much quicker and with greater intensity than they did in the first part of the series, often against his own will. As has been seen during Naruto's training sessions, even the slightest amount of frustration on Naruto's part allows the demon fox's chakra to leak out in excess, and Naruto rapidly progresses to a four-tailed state.

The Seal
Jiraiya later reveals that Naruto's four tailed transformation was his doing by using the toadkey with the same seal on its belly as on Naruto's. He had the toad "twist the seal" a little which resulted in the fox's chakra taking over. Jiraiya mentions the Fourth split the demon fox's chakra in two halves, sealing the Yin chakra making it inaccessible to Naruto, but sealing the Yang allowed Naruto access to it.

Influences
The is a well-known character in Japanese folklore, and the influence behind not only the demon fox but many other reincarnations in modern Japanese culture. It likes to play tricks and pranks on people, and on occasions transforms itself into a beautiful woman and seduces a man (obviously the inspiration for Sexy Technique). Also, Kitsune are known to keep their promises, a trait Naruto has; his ninja way is to "never go back on [his] word." It should also be noted that every time Naruto loses control and is overwhelmed by the demon fox's chakra, he seemingly gains another "tail" of chakra. This stems from the belief that the more tails a kitsune has, the more powerful it is, with nine tails usually being the limit.

Also See
Naruto Jinchuriki Forms