Shukaku was said to be the corrupted spirit of a Sand priest who was imprisoned within a tea kettle. Current information suggests Shukaku is a "bijuu", one of the tailed demons of the ancient world. He has been in the possession of Hidden Sand since ages past. When Karura became pregnant and had Shukaku imbued into her son, she cursed the village for what they had done. When Gaara was later born she lost her life in the process. Gaara grew up confused and angry at his place in the village, as all the villagers feared him and his power to control the sands. When Gaara grew older he gained the ability to enter into a forced sleep, which would allow Shukaku to come out. Shukaku would gather sand from the surrounding area to make his large tanuki body. Shukaku seems to be fairly loud and flamboyant in his speech, probably as a result of not being released very often.

The Akatsuki criminal organization sought to obtain Shukaku from Gaara for their own diabolical ends. Demon imbued persons are called "jinchuuriki" by Akatsuki, literally "the power of human sacrifice". This seems to stem from a life being lost when the demon is imbued into the individual. For Gaara, his mother lost her life to imprison Shukaku. When Akatsuki captured Gaara they took him to their cave in the River Country and placed him before their large statute. They then performed a jutsu which seems to withdraw the Shukaku spirit from out of Gaara's body.

Nibi and Yugito were captured by Akatsuki for their own diabolical plans. The group removed the demon from Yugito's body, killing her.

Because Sanbi was "in the wild," he was weaker. This was because he could not properly control his power. Tobi was assigned to capture this demon and did so with the assistance of Deidara. An unconscious Sanbi was then taken back to Akatsuki's base of operations. There he was sealed away in the King of Hell Statue.

The power of the Kyuubi has affected Naruto in several ways physically. When Naruto's body becomes injured, the power of the Kyuubi will leak out and heal Naruto's body at a very quick pace. Also, when Naruto experiences emotional experiences the chakra and power of the Kyuubi begins to leak out and turn Naruto into a more feral individual. At first he had little control over the ability to draw on the Kyuubi's chakra, but the Sannin Jiraiya taught Naruto how to reach deep inside himself and convince the Kyuubi to give him extra chakra when needed. This large additional chakra allows Naruto to perform Kage Bunshin on a very large scale and also summon the Toad Boss Gamabunta.

The Akatsuki criminal organization has expressed interest in obtaining the Kyuubi from Naruto for their own diabolical ends, though they have yet to accomplish this goal.

The jutsu to call the Shinigami forth was taught to the Third Hokage by the Fourth Hokage. Calling him forth will result in the casters death however, because in exchange for the Shinigami removing the soul of the target, it will take your own soul in exchange. Both souls will forever after be condemed to damnation, fighting eternally in the stomach of the Shinigami.

After being summoned Tayuya can control these Doki with the melodies of her flute. One melody will cause the oni to release their pure material ghost form from their mouth, this ethereal form can move through objects. When it comes into contact with a living being, it will eat away at their physical energy.