Dark Gift of Sadistic Regeneration

Your murderous rampages allow you to regenerate your health as long as you continue to kill. You gain the following "benefits":

• As a Bonus Action, you may expend one of your Hit Dice, roll it twice, choose the higher result and add your Constitution modifier. You regain that many Hit Points.
• You no longer regain Hit Points and expended Hit Dice when finishing a long rest.
• Whenever you kill a humanoid creature, you regain expended Hit Dice equal to the number of Hit Dice that creature possessed, up to your maximum.