Jinchūriki

The are humans that have a tailed beast sealed within them. They exhibit extraordinary powers, and in some cases are more powerful than their tailed beasts, because they have the intelligence to use the beast's powers effectively.

The first jinchūriki was the Sage of Six Paths, who sealed the Ten-Tailed Beast within himself to save the world, but before his death, the Sage divided the Ten-Tails' chakra into nine separate tailed beasts and sealed the Ten-Tails' body into the moon. The Second Kazekage of Sunagakure was the first to research the jinchūriki, with the other villages following soon after. Each village has used a different seal when creating their jinchūriki, resulting in different levels of access to the beast's chakra. For example, Konohagakure used the Dead Demon Consuming Seal, while Akatsuki, an organization whose role in the series is to capture the jinchūriki, uses the Illusionary Dragon Nine Consuming Seals to extract the tailed beasts, and seal it away for future use. They have, as of the Fourth Great Shinobi World War, captured seven of the nine beasts.

Personality
Jinchūriki are typically lonely people, viewed by those around them as the beast that has been sealed within them, leading to prejudice and being hated and feared. According to Akatsuki, the first two jinchūriki they captured loathed humanity, and their villages were in fact glad to be rid of them. However, certain villages treat their jinchūriki with respect, thus leading them to have different personalities than those who are shunned. Such examples are Yugito Nii and Killer Bee, both from Kumogakure.

As the jinchūriki draws on more of their beast's power, their personality tends to corrode into animalistic instincts. Because their survival depends on the safety of their hosts, the tailed beasts are very protective, and will act whenever their hosts' lives are in danger. Normally, these hosts have little control over themselves as they transform deeper into their tailed beast forms, and become more beastly in battle. However, Yagura and Killer Bee, the only two jinchūriki to have full control of their tailed beasts, can retain complete consciousness and control even after a full transformation.

Abilities
Jinchūriki have access to a unique fighting style, depending on their tailed beast: Gaara controls sand, Yugito controls fire, Rōshi controls lava, Killer Bee can spit ink, and Naruto has high stamina and rejuvenation. By training, they can gain additional access to their tailed beast and its chakra, such as Killer Bee being able to synchronize with his beast, and transform himself into it. Not all jinchūriki can retain control when transforming into their tailed beast; when Naruto taps into his four-tailed form, he loses the ability to discern between friend and foe, and attacks anything in sight. A tailed beast can also provide its host with constant advantages, such as Gaara's self-activating Shield of Sand which automatically protects him, even from self-injury and Naruto's healing factor that immediately activates as soon as he incurs wounds.

Known Jinchūriki

 * Gaara
 * Beast: One-Tailed Shukaku
 * Affiliation: Sunagakure
 * Status: Captured and extracted by Akatsuki; later resurrected by Chiyo with chakra from Naruto


 * Yugito Nii
 * Beast: Two-Tailed Monster Cat
 * Affiliation: Kumogakure
 * Status: Captured and extracted by Akatsuki; deceased


 * Yagura
 * Beast: Three-Tailed Giant Turtle
 * Affiliation: Kirigakure
 * Status: Extracted under unknown circumstances; deceased


 * Rōshi
 * Beast: Four-Tailed Monkey
 * Affiliation: Iwagakure
 * Status: Captured and extracted by Akatsuki; deceased


 * Han
 * Beast: Five-Tailed Dolphin Horse
 * Affiliation: Iwagakure
 * Status: Captured and extracted by Akatsuki; deceased


 * Utakata
 * Beast: Six-Tailed Slug
 * Affiliation: Kirigakure
 * Status: Captured and extracted by Akatsuki; deceased


 * Fū
 * Beast: Seven-Tailed Horned Beetle
 * Affiliation: Takigakure
 * Status: Captured and extracted by Akatsuki; deceased


 * Killer Bee
 * Beast: Eight-Tailed Giant Ox
 * Affiliation: Kumogakure
 * Status: Active


 * Naruto Uzumaki
 * Beast: Nine-Tailed Demon Fox
 * Affiliation: Konohagakure
 * Status: Active


 * Sage of the Six Paths
 * Beast: Ten-Tailed Beast
 * Affiliation: Unknown
 * Status: Separated its chakra into the nine tailed beasts and trapped its body in the moon; deceased

Similar Cases
In the anime, Sora only had a part of the Nine-Tails' chakra sealed into him, which made him a "pseudo-jinchūriki." Even though he was granted similar abilities to those of a real jinchūriki, his were vastly inferior.

In Naruto Shippūden 2: Bonds, Amaru had the Zero-Tailed Masked Leech sealed within her, but because the Zero-Tails is not an actual tailed beast, Amaru is not considered a jinchūriki.

In the anime, Yūkimaru had the ability to control the Three-Tails. While his appearance is similar to that of Yagura, the Three-Tails' former jinchūriki, with the same distinctive eye and hair color, no confirmed connection exists between the two. The tailed beast was not actually sealed inside of him, and, thus, he was not a real jinchūriki.

Trivia

 * Four of the known jinchūriki each have some relation to a Kage, specifically, the fourth in their respective villages; Naruto is the son of the Fourth Hokage, Gaara is the son of the Fourth Kazekage and is the Fifth Kazekage, Killer Bee is the brother of the Fourth Raikage, and Yagura was the Fourth Mizukage. Gaara and Yagura are the only known jinchūriki to have been the Kage of their village.
 * Gaara is the only known jinchūriki to have lost his tailed beast and live. Although he did die during the extraction, he was revived shortly after by Chiyo. Even after Gaara's tailed beast was extracted from him, his powers still remain intact. This is unclear whether the other jinchūriki could have kept their powers if they were still alive after the tailed beast's extractions.
 * Naruto Uzumaki and Yugito Nii are the only known jinchūriki to have known surnames.
 * Takigakure is the only village, not belonging to one of the Five Great Shinobi Countries, known to have had a jinchūriki.
 * Yugito and Fū are the only known female jinchūriki.
 * Yagura and Killer Bee are the only known jinchūriki that are said to have full control of their tailed beasts.
 * Despite being an anime-only classification; Utakata is the only jinchūriki known to be a missing-nin.