Dead Demon Consuming Seal

The Dead Demon Consuming Seal is a sealing technique developed by the Uzumaki clan to call upon the power of the Shinigami. Its very existence is so secret that even Orochimaru knew nothing about it.

Overview
After the hand seals are performed, the user's soul is partly separated from their body and suspended behind them. Behind their soul appears the Shinigami, which restrains their soul with its hair. Only the summoner is able to see the Shinigami at this point. After a few moments, the Shinigami wraps its left arm with prayer beads and chants unintelligibly until a cursed seal appears on its arm. It then drives its arm into the summoner's soul, thus allowing the summoner to call upon the Shinigami to seal a target: the Shinigami's arm emerges from the summoner's body and grasps the target's soul. When Hiruzen Sarutobi performs it, he is required to get close to his target in order to initiate the seal. When Minato Namikaze performs it, he is able to remain at a distance. Targets are able to see the Shinigami so long as it's in contact with their soul.

While the Shinigami grabs their soul, the target is immobilised, any jutsu they may be using are dispelled, and they are prevented from performing additional jutsu. With targets unable to escape or fight back, the summoner can remove and seal their soul. Hiruzen was able to seal multiple souls by using this technique in conjunction with the Shadow Clone Technique. The sealing, however, is not necessarily complete nor automatic:
 * When Minato uses it, he seals only the Nine-Tails' yin chakra, leaving its yang chakra alone.
 * When Hiruzen used it on Orochimaru, he had to rely on his own physical strength to extract Orochimaru's soul. Because he lacked the strength to fully remove it, he opted instead to only seal Orochimaru's arms, accomplished by having the Shinigami cut off the arms of Orochimaru's soul.

The target's soul is sealed within the body of the summoner, represented by a swirl pattern on their torso that is similar in appearance to the Eight Trigrams Sealing Style. In Minato's case, this sealing of the Nine-Tails' yin chakra into himself makes him its jinchūriki. With the sealing completed, the Shinigami gradually starts consuming the summoner's soul. The summoner can, with difficulty, continue moving and speaking, allowing them to finish any lingering business they may have, but they will die as soon as their soul has been fully consumed. The souls of the summoner and their victim do not pass on to the Pure Land, instead being trapped within the Shinigami's stomach, destined to fight each other for all eternity.

Although Orochimaru survives the sealing of his arms, his arms are paralysed, causing them to hang uselessly at his sides. This prevents him from performing hand seals and by extension most ninjutsu. With time, he's able to regain limited use of the arms, but he's still left with a constant and extreme pain. Orochimaru believes that Tsunade could heal his arms - something Tsunade does not deny - but she refuses to help him. Ultimately, after his arms begin to rot, Orochimaru is forced to switch bodies or risk death. He is able to make better use of the new body's arms, but the jutsu he can use remain limited so long as his soul's arms are sealed within the Shinigami.

Souls can only be freed from the Shinigami's stomach by using. To use, an individual wears the Shinigami Mask, causing them to become possessed by the Shinigami. If the individual wearing the mask slices open their own stomach, the Shinigami will do the same, and any souls inside it will be freed. However, the mask doesn't have any properties that will prevent its user from dying of that injury; when Orochimaru uses this to restore his arms, he survives the injury by switching bodies once again. With the other souls he frees from the Shinigami, Orochimaru is able to use the Impure World Reincarnation.

Trivia

 * The full name of this technique is.
 * Tō no Sho lists the Dead Demon Consuming Seal as having a range of up to five meters. When Minato uses it against the Nine-Tails, he does so from significantly further away.
 * During his discussion with Kushina on how to deal with the Nine-Tails, Minato stated: . What he meant by this is unclear.
 * What Minato may be implying with this statement is that since jinchūriki already have a tailed-beast inside them, they are unable to seal another's chakra inside of them, whether because the technique simply can't consume three different chakras, it is impossible to seal three different chakras into one person, or that using this technique with a tailed-beast sealed inside the user will simply cause the Shinigami to instantly consume the user's and the tailed-beast's chakra (as they are already sealed inside the user as is what the jutsu would do to the intended target), is unknown.