Unnamed spell

This spell can heal the gravest of wounds, no matter how life-threatening. At the DM’s discretion, depending on how life-threatening the wound is, this spell can either stabilize an unconscious PC, making them succeed all three death saving throws no matter the past rolls, or heal 200 hit points worth of damage to one PC. However, this spell has no effect on a PC who has already failed all 3 death saving throws. 

Using this spell comes at a cost to the recipient, though. This spell uses some of the recipient’s life force to heal the wound and stabilize them. The DM rolls a d10, and that roll is how many years is taken off of the recipient’s lifespan. The DM can either choose to take that in the form of the PC aging that many years, or to take into account when making deals with otherworldly beings. This spell will also bind the recipient into the servitude of the caster once the recipient dies. When the recipient does die, they stabilize in their death and cannot be raised from the dead by anyone other than the original caster. Only a Wish can remove the recipient from service of the caster, and only after they die.