The Death Reaper Seal is a seal developed by the UZUMAKI CLAN to call the power of the Shinigami After the hand seals are performed, the user’s souls is partly separate from their body and suspende behind them. Behind their souls appears the Shinigami, which restrains their souls with its hair. Only One the summoner is able to see the Shinigami at this point. Eventually, the Shinigami wrap its left arm with prayer chants and beads unintelligibly until a Cursed Seal appear on it’s arm. It then drives its arm into the summoner’s souls, those allowing to the summoner to call upon the Shinigami to seal a target.
1 -> Minato Namikaze
Minato first summoned the Shinigami, as a last resort, with the intention of sealing nine tails into his His Son he Shinigami main strength is lies in it’s ability to forcibly extract the souls of both its summoner and its summoner target, cut them free with its tanto knife, and seal them with in its belly.
2 -> Hiruzen Sarutobi
When it is introduced by the 3th Hokage Vs Orochimaru, Hiruzen said that the souls of the victim and its user is forever inside the Shinigami. It that in the case, then there is a lot incompatibility During the Orochimaru vs Hiruzen fight, we see that Minato is almost being by Edo Tensei back alongside the First and Second even though later we find out he also died by The Death Reaper Seal Jutsu, so he can’t actually be summon according to Hiruzen explanation of the jutsu.
3 -> Orochimaru
Orochimaru In an attempt to free the former Hokage’s souls from the Shinigami stomach, Uzumaki Clan’s Mask Storage Temple to pickup a mask from the ruins, and then took the Sasuke and others to the underground hall in the Uchiha Clan Naka Shrine Orochimaru proceed to don the mask which invoked the Shinigami’s to possess his body. Orochimaru cut open the Shinigami stomach, a wound reflect on his own body, to release the trapped contents inside the Shinigami stomach. And Undo The Death Reaper Seal And Take Out the former Hokage’s souls from the Shinigami stomach And perform on them reanimation jutsu.