Shukaku, also called Shukaku the Sand Spirit and the One-Tail, is one of the nine Tailed Beasts in the Naruto and Shippuden manga and anime series, being the Hidden Sand Village and its jinchuriki had.
Background EditShukaku first came into existence when Hagoromo Otsutsuki, the man known as the Sage of Six Paths, divided the chakra of the original tailed beast, the Ten-Tails, up into nine seperate entities. Hagoromo named Shukaku and the others and told them one day they'd be as one again, as well as that they'd always be together, even if apart. Shukaku's history after this is largely unknown, though centuries later he was captured by the elders of the Hidden Sand Village and sealed away as their ultimate weapon within various jinchuriki. One of these, Bunpuku, Shukaku grew to respect some and felt, contrary to the man himself, that he'd never get another jinchuriki like him. Another was the one whose sand control abilities influenced the Third Kazekage to create his Iron Sand jutsu. He was extracted from both of these jinchuriki, resulting in their deaths. Eventually, Shukaku's third jinchuriki became Gaara, who was not able to control his powers and often killed or injured others without meaning to. In an attempt to test Gaara one last time, his father's order only resulted in Shukaku being unleashed when Gaara lost control, forcing his father to suppress it.
Fighting for GaaraDuring his battle with Naruto in part 1, after Gamabunta cut his right arm, Gaara emerged from within his full Shukaku transformation and used the Play Possum Jutsu to allow Shukaku to fight in his stead. Delighted to finally be free again, Shukaku relished the chance to kill Naruto and Gamabunta and began using his Wind Style to fight the two, nearly killing the latter. When it became clear that Shukaku was too much to handle normally, Gamabunta and Naruto performed a Combined Tranformation jutsu to change into a giant fox(though in the anime it was Kurama, the Nine-Tailed Fox) to be able to cling to Shukaku and allow naruto to punch Gaara awake, suppressing Shukaku before his powers fully awoke.
ExtractionIn part 2, Gaara was targeted by the criminal organization called the Akatsuki, with one of its members, Deidara, battling him. During the fight, Gaara proved more powerful, using Shukaku arms and his vast powers to keep Deidara on the dodge for most of the fight, nearly killing him more than once and crushing his left arm. Deidara still managed to win by intelligence, however, and took Gaara captive back to the Akatsuki's hideout where, despite many being sent to rescue him, Shukaku was extracted from within Gaara, killing him, and sealed away inside the Gedo Statue, the empty vessel of the Ten-Tails, where he remained for much of the rest of the series. Gaara was, however, later revived and had retained Shukaku's powers.
Brief freedom and recaptures
During the Fourth Great Ninja War, Shukaku and most of the other tailed beasts, along with portions of Gyuki and Kurama's chakra, were absorbed by Obito Uchiha, the Akatsuki's leader, allowing him to become the incomplete Ten-Tails' jinchuriki. They were, however, later freed by the combined efforts of most of the shinobi alliance, and Sasuke Uchiha, allowing Shukaku to assume a physical form of its own outside of Gaara, along with the other beasts. When Gaara asked him to help him seal Madara, Shukaku agreed on the notion that it was a chance to show up and surpass Kurama, with the other Tailed Beasts also joining them. When they later ecountered Madara, now fully resurrected and restored to full power, their combined efforts allowed them to easily overwhelm him at first, with Shukaku sealing Madara inside a giant sand pyramid, only for him to break out with Susano'o. Though Naruto and Killer B joined them and they shattered this and ripped Madara's arm off, a White Zetsu clone arrived and returned Madara's right Rinnegan to him. From there, the tide the fight turned overwhelming against Shukaku and his teammates, and they were all, despite resistance, defeated and re-sealed with the Gedo Statue by Madara, who proceeded to use them to revive the Ten-Tails again, more complete this time, and absorb it into himself, becoming the new jinchuriki of the legendary monster. Some of Shukaku and Gyuki's chakra was later recovered by Obito after he betrayed Madara, and presumably sealed inside Naruto, along with Kurama's other half to save his life, with Shukaku then being able to give him aide against Madara whe he and Sasuke Uchiha engaged the mighty ancestor in battle. After Madara's betrayal by Black Zetsu and the ultimate defeat of Kaguya, Shukaku and the others were freeded again, but we quickly imprisoned by Sasuke in Planetary Devastation spheres until Naruto defeated him in battle and reformed him from his ruthless intention to kill them, at which point Shukaku and the others were freed again. His further fate beyond this point is unknown.
Shukaku's initial persona was very demonic; he was openly and cheerfully evil, and thirsted to kill anything in sight. This was shown when he engaged Gamabunta and Naruto in battle. Gaara noted his blood lust was even greater under a full moon. Shukaku also has a deep hate of Kurama due to his belief that the Tailed Beasts' strengths are determined by their number of tails, and he will readily do anything to show up Kurama and try to surpass him. He also seems to have developed a respect and care for Gaara, seeing in him similar qualities that one of his other jinchuriki that he respected had, defending him from Madara Uchiha's attack.