Shinigami Contract

Shinigami Contract as the technique itself that create the contract between man and Shinigami. The jutsu itself is very costly, however it can be said the powers gained from serving the Shinigami make this a fair trade. To use one must attain another human being, and keep them near the brink of death until the end of the technique. The user will draw a large circle on the ground in the blood of the "sacrifice". Then they will push their bloody palm print on the center, expelling near all of their chakra. This, will summon the Death God.

From here, he will take the soul of the sacrifice, and "damage" the soul of the user, as well as creating a life-long contract with them. They are given a dominion over death, and it is now their job as the Shinigami's servant to cause it. From here on out, whenever the user kills another directly, their soul is sealed and rests within the user's belly. These souls cannot be removed except for by the user's own Shinijutsu. Each soul gives a small benefit, however together the benefit is strong. Each soul gives the user the spiritual energy of the deceased, which does not increase their chakra supply directly, but allows them to generate more chakra. Further, each soul expands the user's own lifespan by 50 some years, dependent on the soul.