Legend has it that there exists an order of immortal warriors who are known to steal the life from others in order to extend their own. These monks have learned to use the power of death against it. While not having a pure lust for blood (although some develop a constant desire to kill) these monks benefit from the harm and death of their enemies. With each strike they drain their foes of their vital essence while empowering their own, becoming what most can only see as immortal.

Fist of the Immortal

When you follow this monastic tradition at 3rd level, you learn to steal the life force of your foes and make it into your own. Your attacks deal necrotic damage. Once per turn whenever you hit with a monk weapon or unarmed strike you can cause one of the following effects to occur:

-You heal half the amount of necrotic damage dealt

-The target cannot take reactions until the end of your next turn.

-You spend 1 ki point and force the target to make a constitution saving throw. On a failed save, you reduce the target's maximum hit points by the amount of damage dealt

Vital Interference

Starting at 6th level, your manipulation of life and death grants you the ability to inhibit your enemies constitution. When you hit with an unarmed strike, you can spend 1 ki point to force the target to make a constitution saving throw. On a failed save, the target suffers from one level of exhaustion. You cannot force a target beyond three levels of exhaustion. You can use this ability an amount of times up to half of your proficiency bonus (rounded up). You regain all expended uses when you finish a long rest.

Enhanced Strikes

Your strikes are those of legends. Starting at 11th level, your punches ignore resistance to necrotic damage, and any immunities are reduced to resistance. Also, whenever you use your Stunning Strike, you can spend an additional ki point to ignore Stun immunities.

True Immortality

Starting at 17th level, you've become a legend among immortals. As a bonus action, you can spend 5 ki points to enter your True Immortal state. This lasts for one minute unless you dispel it (no action required), are incapacitated, or die. While in this state you are resistant to all but psychic damage and you gain the following abilities:

-You can use the healing factor of your Fist of the Immortal technique on every successful strike rather than only once. You are only able to heal in this fashion.

-You have advantage on Constitution saving throws.

-Whenever you reduce an enemy to 0 hit points you can preserve its life force for later. You can store up to two preserved life forces at a time and keep them even outside of your True Immortal state. When you or an ally you can see are reduced to 0 hit points, you can use your reaction to transfer the preserved life force to the dying target, healing them to half of their maximum total hit points. You can do this a number of times equal to your Wisdom modifier. You regain all expended uses after a long rest.