Summoning: Six Paths Sealing Box

The Six Paths Sealing Box is a forbidden sealing technique that rivals the power of Chibaku Tensei.

History
Back in the times of Sage of the Six Paths, Hagoromo's brother wanted to develop a sealing technique that could contain his brother's monstrous creations, the Tailed Beasts. Convincing his brother it would protect future generations of shinobi from another Kaguya, Hamura and Hagoromo used their Six Paths Yin Power and Six Paths Yang Power seals to make the powerful box. The box became branded with three symbols, a sun, a moon, and a Rinnegan ripple. This was to show that you needed those three to use the power of the box. After Hagoromo saw through his brother's true intentions for the box, he changed the seal, making it impossible for Hamura to use it without his chakra. He later passed on the duty of protecting the box to his youngest child Asura, who then passed it on to his descendants, the Uzumaki Clan. After many years of protecting the box, the clan had mysteriously been wiped out. The box was remained a secret from the shinobi world, since it was hidden under the ruins of the clan's hidden village. This all changed when both seals appeared for the first time in years, and the box began to slowly remove the seal placed on it by Hagoromo. After the reincarnations once again resurfaced after the Fourth Shinobi World War, Asura's reincarnation Uzo decided to go find it, and went to the ruins. He ultimately found the box, but was unable to open due to his lack of missing seals. He was found by Shai Uchiha, who possessed the final two keys. Challenging him, Uzo lost, and was turned into a puppet by Shai. Intrested in the box, Shai used his Six Paths of Pain technique, giving Uzo his own Rinnegan. The eye turned out to be the final key to unlocking the box, and the two were finally able to awaken it. Shai allowed Uzo to make a contract with the box, due to the enormous amount of chakra needed to use it. The box is now used by Uzo, who uses it to seal Tailed Beasts for Shai.

Contract Process
In order to make a contract with the box, the user must make a circle of blood around the box, and put two hands of blood on the seal. The circle will then turn white, and a flash of light will erupt from the spot. The user must keep their hands on the box, or the contract process will end. As the hands are on the box, the box drains and enormous amount of chakra from the user, and will deplete it to zero. However, an Uzumaki or Senju clan member posseses the life force to survive the draining, allowing them to continue the process. The white light will turn dark, and will begin to collapse upon the user. The box becomes tainted with the chakra signature of the user, ulultimately giving the user the ability to summon the box.

Abilities
This box has the ability to seal almost anything within it, being made to seal all nine Tailed Beasts if needed. It also has the power to absorb chakra, and can transfer it to the user if wanted. The box can generate a powerful barrier, depending on how much chakra is contained within it.

Drawbacks
Despite being a powerful technique, it comes with risks. The first of these is the chakra needed to summon and activate the box. Unless the user is a Uzumaki or Senju, the box will be unable to use, becoming a waste. Another risk of the box is the barrier it generates. If the barrier drains the chakra of the box, it can allow the contents within to disappear, unless the user offers up their own.