I have recently conjured up a theory about the Uzumaki Clans Shinigami Mask, possibly the remaining mask left in the temple were also used to reverse sealing techniques that were seemingly irreversible? What I can concur is that there were 27 different Shinigami Mask, and of those 27 one was taken (to reverse the Reaper Death Seal technique), but to what serve the other 26 mask, and other possible side effects? (Orochimaru had to be sacrificed in order to perform the reversal of the Reaper Death Seal) Here are a couple theories..
- Reversing twenty-six other Sealing techniques.
- The user must sacrifice him/her self and/or others.
- The user must seal one or several body parts forever.
The Uzumaki Clan were heavily known for their sealing prowess, and it was also stated that their sealing processes "were a little rough.". I believe when they state the sealing process to be "rough", I deduce this statement to meaning sacrificial of oneself/others or belongings. (body parts etc.) That being said, the huge tole of such Sealing techniques were because they were the most feared due to their power in Kushina/Minato's Era. Mito Uzumaki, being able to seal Kurama within herself (able to seal a Bijuu takes an advanced Sealing technique) while also suppressing her chakra was a clear acknowledgment of the said statement.. The masks could have possibly been used to seal Kurama inside of early Uzumaki hosts.
- The Uzumaki Clan's other 26 Shinigami Mask (except the one used by Orochimaru as we've seen the use) could possess reversal sealing power.
- All 27 Shinigami Mask have a permanent "side effect" to the user of the Shinigami Mask.
- Uzumaki Clan's Shinigami Mask possibly could have also not just reversed sealing, but used to seal stronger targets example: To seal Kurama repeatedly in early Uzumaki host.
Addition by Noddy:
Originally Posted by Noddy
Addition by SasoriOfTheRedSaand:
Originally Posted by SasoriOfTheRedSaand