Shukaku first came into being in the waning days of the Sage of the Six Paths, who used his Creation of All Things ability to separate the Ten-Tails' chakra from its body and divide it into nine separate constructs that would come to be known as tailed beasts in order to ensure that it would never resurface after his death. Some time after being created, the Sage sat down with all the young tailed beasts and told them that they would always be together, even when separated, and that one day they would become one entity again with different names and forms than they did. Then, when the time came, they would know what true power is.
Shukaku would eventually be captured and kept by Sunagakure, to which the First Kazekage, who was invited along with other first Kage by Hashirama Senju into the first summit, attempted to use his possession of the tanuki as leverage to gain wealth for his nation, as opposed to gaining another tailed beast.
One of Shukaku's first jinchūriki before Gaara was a Suna priest named Bunpuku, who was locked away in a dungeon with the giant tea kettle, and was kept under constant guard. Over time, the citizens of Sunagakure came to believe that Shukaku itself was a living ghost of a corrupted priest sealed inside a tea kettle. Despite the animosity the village showed for Shukaku and its host, the elderly priest held no ill-will towards the tanuki nor the villagers, viewing it as as an equal and was content as long as Shukaku hadn't forgotten his name. Shukaku eventually came to appreciate Bunpuku and would later remember the words he imparted to it: that someday someone would appear in the world to teach it about the heart and acceptance.[9] Shukaku's another jinchūriki before Gaara was the one who inspired the Third Kazekage to create his Iron Sand fighting style. Shukaku was eventually removed from their bodies, resulting in their deaths.[
When Karura became pregnant with Gaara, her husband, the Fourth Kazekage, had Chiyo seal Shukaku into Gaara while he was still in the womb because, out of his three children, Gaara was the only one compatible with the tailed beast. Before Karura died after giving birth, she passionately told her son that she would protect him, and, according to her husband, her love seeped into the sand and was noted to form his automatic defence. However, Gaara couldn't properly control Shukaku's powers, killing or injuring several of Suna's shinobi and citizens by accident. Shukaku would even site his hatred toward humans, warning Gaara not to sleep too long if he didn't want to give Shukaku an opening. Deemed a failure, the Fourth Kazekage chose to test his son one last time, ordering Yashamaru to assassinate him and also tell him that his mother never loved him, and that she was used as a human sacrifice for the sealing process. Gaara failed the test, fully releasing the rampaging Shukaku, to which the Fourth eventually used his Gold Dust to subdue the tanuki.
During Gaara's time as the Fifth Kazekage, Deidara and Sasori from the Akatsuki were assigned to capture Shukaku. After Deidara defeated Gaara in combat and took him to Akatsuki's lair in the Land of Rivers, Shukaku was forcefully extracted from Gaara and placed within the Demonic Statue of the Outer Path. Though the extraction killed him, Gaara was resurrected through Chiyo's One's Own Life Reincarnation technique and has still retained the ability to control sand.
Shukaku was the only tailed beast sealed within the Demonic Statue to have not been resealed into Obito Uchiha's Six Paths of Pain and as such, did not meet Naruto during his encounter with the other tailed beasts. When Naruto proceeded in his plan to pull all the beasts from Obito's body in order to halt the Shinju's flower from blooming and completing the Eye of the Moon Plan, its chakra rejected Naruto as he contained none of the tanuki's chakra. Gaara, having been bonded with Shukaku, instead took hold and began pulling the chakra himself. Through the efforts of the Kazekage, Shukaku was freed from its captivity alongside the other tailed beasts. Upon being freed, Shukaku started to recognise Naruto. Despite showing reluctance to Gaara's request for its help in sealing Madara Uchiha, Shukaku decided to do so only for the opportunity to surpass Kurama.
When Madara ran towards them and the other tailed beasts, both Shukaku and Gaara conjured numerous sand bullets and were able to restrain the Uchiha's movements. Despite them forming the Desert Layered Imperial Funeral Seal, Madara managed to escape the sand pyramid with his Susanoo. As Naruto in Tailed Beast Mode pinned Madara down with a tail, Shukaku and the other tailed beasts joined in and did the same to increase the damage, but the Uchiha survived their attacks and retreated to a safe distance. After he received his own right Rinnegan eye from a White Zetsu clone, Madara quickly summoned the Demonic Statue of the Outer Path from Obito's body, and used the Rinnegan to repel the tailed beasts.
With the tailed beasts stunned, Madara then proceeded to chain them up and prepared to seal them back into the statue. As Madara began the process on Shukaku, Gaara intervened, declaring his refusal to let Madara get his former tailed beast. Shocked at how determined Gaara was to protect Shukaku despite their negative past, the tanuki remembered Gaara explaining that he'd been grateful to Shukaku as it was thanks to the tanuki that Gaara had met his first friend, Naruto. As Madara launched an attack on Gaara, Shukaku quickly blocked the attack for its former jinchūriki. Despite their new-found team-work, Madara still rebuffed their efforts. Ultimately, Shukaku, along with the other tailed beasts, are all resealed within the Demonic Statue.

Throughout the years Shukaku was again freed and then thought to finally be destroyed - though the very way that this had happened or who had accomplished such a task was lost to the years; with each retelling of the story becoming farther and farther to the truth. When Shukaku reappeared centuries later, the reincarnation of the beast he once was, it was even said to be lost to him. He would become violent if pestered with the wanting of said knowledge; and therefore the subject was often dropped.
Shukaku spent much of his time roaming the Chakra Beast Valley until boredom set in for the blood crazed beast. He still had much of the same personality and traits that he had had before, and the bloodlust was one of them. Therefore he set out into the world, heading for the warmest place that he could find which was Yokuchi. The plague that ravished the lands didn't bother him as he traveled as nothing more than blowing dust on the wind, or at other times as the huge raging beast that he was.
Eventually, with a path of bloodshed like a trail of bread crumbs behind him, he arrived in Yokuchi: only to find himself facing a shinobi much like the one from his past - a sand manipulator who weilded a great deal of power... he would test this shinobi, and grant her his loyalty as she proved herself an effective candidate to have his power weilded by once more.

Name: Absolute Defense
Type: Supplementary, Defensive
Requirements: /
Ability Tier: Tier 4
Minimum Rank: Jounin (A)
Description: The user's sand (including that in the gourd) is now infused with not only the hosts chakra but the beasts itself. As such the beast is capable of protecting the host now completely on its own free will. Knowing that it will die if the host dies, the beast will always protect the host. Due to the beasts SS rank it is capable of protecting against all physical attacks (Taijutsu and Kenjutsu) up to and including SS rank. Likewise the user is protected against Doton and Fuuton based attacks up to SS rank as well as well as other Sand attacks of S SS rank and lower.
However, Katon based attacks do an additional +2 Damage to the user. Raiton of equal rank to the user is capable of penetrating the sand. Raiton of S rank is capable of glassing the sand, all Raition attacks A rank and lower is blocked. Suiton causes the shield to slow, changing its movement speeds from that of SS rank to A rank.
Since its whole body is completely made of sand, Shukaku can ignore most damage that would otherwise be detrimental.

Name: Sand Generation
Type: Supplementary
Requirements: /
Ability Tier: Tier 4
Minimum Rank: Jounin (A)
Description: The user is capable of generating mass amounts of additional sand to use for the purpose of jutsu (up to 100 pounds of sand per post), or even using the beasts own sandy body to add to their own supply for their own usage (when done this way the user is capable of creating more than 100 pounds of sand per post).

Name: Sand Manipulation
Type: Supplementary, Offensive, Defensive
Requirements: / 
Ability Tier: Tier 4
Minimum Rank: Jounin (A)
Description: The user is capable of freely manipulating not only their own sand (that within their gourd which has been infused with their chakra) but also the sand granted to them by Shukakau: this is done with the simpliest of gestures and costs no chakra due to the sand being so infused with chakra that it is capable of acting of its own free will, or the users will without question, especially when it comes to defending the host the beast is sealed within). This sand manipulation can even stretch to the manipulation of sand present in the enviroment.

Name: Form Manifestation
Type: Supplementary, Offensive, Defensive
Requirements: / 
Ability Tier: Tier 4
Minimum Rank: Jounin (A)
Description: The jinchuuriki is capable of manifesting and using different parts of the beast at any given time: head, front legs, back legs, tail, ect (which takes 1 post to manifest). This also includes a full blown beast form transformation (which takes 2 posts to manifest).

Name: Partner Bond
Type: Supplementary
Requirements: /
Ability Tier: Tier 4
Minimum Rank: Jounin (A)
Description: The users of this power are able to form a sacred and powerful union between user and companion both telepathic and empathatic, and they can fight with a harmonized flow of energy. The user can also just rely on their companion to fight. 
Both are linked both emapathically and telepathically at all times.
In some cases if the user is in danger, there can be a fusion between user and companion to achieve a more powerful form.

Name: Wind Style - Drilling Air Bullets
Canon/Custom: Canon
Rank: S
Type: Offensive
Element: Fuuton
Range: 0 - 100 Meters
Specialty: Ninjutsu
Duration: 1 Posts
Cooldown: 3 Posts
Description: To use this technique, Shukaku will first take a deep breath, and then pound its stomach to apply external pressure, the power of which it uses to shoot a highly compressed air ball from its mouth.
 The expelled air ball is mighty enough to hollow out the ground, and level an entire forest. Because of the large quantity of chakra kneaded into it, it explodes the moment it reaches its target, dealing an enormous amount of damage, as well as levelling anything in its path. Shukaku is able to fire multiple of these in rapid succession, having a certain level of control regarding the size of the bullets.

Name: Wind Release: Sand Scattering Bullets
Canon/Custom: Canon
Rank: A
Type: Supplementary, Offensive
Element: Wind
Range: 0 - 50 Meters
Specialty: Ninjutsu | Collaboration Jutsu
Duration: 1 Post
Cooldown: 3 Posts
Description: After the host forms numerous sand bullets/globs/pellets, Shukaku expels a giant gust of wind from its stomach to increase the force of the projectiles. This attack is powerful enough to pierce through flesh with ease. An additional benefit of this attack is that the host can then use any of the sand left in the target's bloodstream to immobilise them, leaving them vulnerable to follow up attacks.

Name: Sand Drizzle
Canon/Custom: Custom
Rank: A
Type: Offensive
Element: Sand
Range: All Ranges
Specialty: Ninjutsu
Duration: 2 Posts
Cooldown: 4 Posts
Description: It is a gunshot-like attack which uses Sand hardened into minuscule grains to attack simultaneously across a vast range. The bullets are so fast that they are difficult to see. After clotting together Sand into countless small lumps, the user uses them to attack an enemy from every direction. Because all the sand lumps are controlled by chakra, it is possible to commence an attack without any blind spots. The moment the user has finished preparing the attack, (Lasting 1 post) evading it becomes extremely difficult. 
If interrupted while preparing, the user must start again. The speed of the bullets is rapidly increased after they are shot. Furthermore, the user can also use an attack pattern where the Sand bullets are shaped into sharp needles, increasing their ability to wound or kill the opponent. Since the Sand can also drenched in poison, defending against this technique is almost impossible. This technique is especially threatening to puppet users, since the puppets can be rendered immobile if the Sand gets lodged into their joints. (Chakra Cost: 25)

Name: Sand Release: Buckshot Bullet
Canon/Custom: Custom
Rank: SS
Type: Offensive
Element: Sand
Range: 200m || 50m AoE
Specialty: Ninjutsu || Shuukaku Jinchuuriki
Duration: 2 post
Cooldown: 5 posts
Description: Gathering a ton or more of his sand into a large ball (Post 1), Shuukaku fires the ball using a blast of wind and sends it flying high over the battlefield (Post 2). Because he maintains control of the sand, he is able to detonate it whenever he wishes; however once the ball is fired it's direction is locked, baring outside influences. Once detonated, the ball explodes downwards in a rain of baseball sized bullets numbering in the tens of thousands. Each ball is extremely heavy and causes serious crush and concussive damage on impact. Broken bones, concussions, internal bleeding are all guaranteed from each impact. Direct headshots are lethal without appropriate armor or defensive ability. The rain of sand balls will create a lake of sand; perfect for leading into other sand based jutsu.

Name: Futon: Shinku Taigyoku [Wind Release: Vacuum Great Sphere]
Canon/Custom: Canon
Rank: S
Type: Offensive
Element: Wind
Range: 20 meters
Speciality: Ninjutsu
Duration: /
Cooldown: 10 posts 
Description: A stronger version of Futon: Shinkugyoku [Wind Release: Vacuum Sphere], the user instead compresses the entirety of an inhaled breath into a single, massive sphere of chakra. This heavily compressed sphere is full of thousands of individual sections of razor sharp air tumbling over each other. The user can then fire it at a target, causing it to rapidly rocket towards the target, tearing through anything it hits with an impressive combination of cutting power and knock back force. The impact is more than enough to kill a man, as being devoured by the sphere would carve someone into thousands of tiny chunks. 5in gashes are common, and this ball of wind can easily cut through a ninja of B-rank or lower, and the body of the target can be thrown back a maximum of 20 feet.

Name: Futon: Shinkugyoku [Wind Release: Vacuum Sphere]
Canon/Custom: Canon
Rank: A
Type: Offensive
Element: Wind
Range: 15 meters
Specialty: Ninjutsu 
Duration: /
Cooldown: 5 posts
Description: The user takes a deep breath and then exhales up to 6 blasts of wind chakra in such a manner that they are dispersed over an expansive range, enough to make it difficult to avoid them entirely without taking any damage. Due to the properties of this technique, the expelled blasts are capable of piercing into and potentially through an opponent's flesh when they collide, in a similar manner to how bullets function; up to 4in deep. The closer the enemy to the user, the higher the chance of full penetration; with someone within 3 meters being the most susceptible to this effect. Baring a strong enough body armour, a hit could prove fatal if taken near (Within 2 inches) of a vital organ or major artery.

Name: Doton: Doryukatsu no Jutsu [Earth Release: Earth Flow Divide]
Canon/Custom: Canon
Rank: B
Type: Offensive
Element: Doton
Range: Short (0-5m), Medium (5-10m), Long (15m+)
Speciality: Ninjutsu
Duration: Lasts until the user removes their hand
Cooldown: Five turns
Hand Seals: Rabbit, Boar, Rat, Horse, Tiger, Snake
Description: The user forms the related hand seals, and places their palms on the ground. Sending a flow of chakra through the ground, the user can tear the earth apart, creating a large chasm. The length, width, direction and curve of the chasm are all up to the user. This technique lasts until the user releases their hands. It costs 25 chakra on the first turn, and 5 chakra per turn afterwards to sustain the effect.

Name: Sand Style Wall
Canon/Custom: Custom
Rank: A
Type: Defensive
Element: Doton
Range: Close (0-5m)
Speciality: Ninjutsu
Duration: Instant
Cooldown: Four Posts
Description: The user creates a solid wall of sand as a form of defence. Chakra is either converted to sand within the body and then spat out to form the wall, or the user can manipulate pre-existing earth to form the wall. The sand then instantly rises up and takes form. The barrier itself is also coated with chakra, it's strength incomparable to that of a normal sand wall. Because of the sand's special characteristics, the wall is highly resistant against, for instance, earth and water. Powerful enough users can create massive walls. The wall can have different designs based on who’s creating it.
This wall can be as thick as ten feet, as long as 50 meters, and as tall as 20 meters; it can be manipulated into different shapes including a full circle to surround an area, making it effect for also trapping opponents as well as protecting allies.