Dead Demon Consuming Seal

This seal invokes the powers of the death god (shinigami). Once called upon, the death god hovers behind the user and inserts its arm into their soul. At this stage only the user can see the death god. To perform the seal the user need only grasp the target. The death god's arm extends from their chest and grabs the soul of the target, immobilizing them and allowing them to see the death god as well. Soon after the sealing is completed the death god consumes the soul of the user as well, sentencing them to an eternity of battle with their target in its stomach. The swirl-pattern of the Eight Trigrams Sealing Style is left on the stomachs of those that have had something sealed within them using this jutsu.

Hiruzen Sarutobi, the Third Hokage, used the Dead Demon Consuming Seal with his last energy in an attempt to take Orochimaru's soul with him, but Orochimaru showed enough resistance against the Third Hokage to escape with his life but without his arms. As the death god had stole Orochimaru's soul's arms, his physical arms suffered from necrosis, causing him extreme pain and unable to use them, all the while corroding as time passes. However, it was implied that such a condition could be healed, as he sought out Tsunade, the world's greatest medical-nin, to do so.

There are many mysteries surrounding this seal, and the exact workings seem to be known to no-one. One of the mysteries is how the Fourth Hokage managed to use this technique to seal the Nine-Tailed Demon Fox within his son, Naruto Uzumaki, rather than inside the death god's stomach, and leave behind some of his chakra to act as a fail-safe capable of communicating with Naruto, in addition to observing what Naruto saw. Also, Hiruzen managed to use this technique through the Shadow Clone Technique to seal the souls of the First and Second Hokage.