The Butcher's Blessing (1.5)

Once per long rest, up until the end of the contract, you may use a bonus action to enter an entirely blood-driven state for 30 seconds.
     • You gain +2 to attack and damage rolls until the blessing ends.
     • All attacks you make critically hit on a roll of 19, along with the regular 20.
     • Whenever you deal the killing blow to a creature while the blessing is active, the timer resets. You may also regain hit points equal to one roll of your hit die + CON mod.
     •You may NOT end the blessing as a bonus action, and at the beginning of each of your turns you must roll a constitution saving throw, DC 19 or the blessing will tax your body, dealing damage to you equal to one roll of your hit die.