Heartless

The sorrowful events of your life you’ve faced have led you to be callous to pain and anguish in others. Whenever you use an ability that would reduce a creature's maximum hit points, it reduces their minimum hit points instead. One per turn, when you inflict a creature with a poison and they fail the saving throw against that poison, you can use your reaction to reduce their minimum hit points by an amount equal to your proficiency bonus.

A creature's normal minimum hit points are 1 hit point. A creature below that HP is considered to be dead, or on death saving throws. When current hit points are reduced further that their minimum hit point threshold, they are treated as if they are at 0 hit points, even if they are not at zero, and have not reached zero hit points. While in this state, your hit points can still be reduced further until reaching zero. You do not wake up from being unconscious until your hit points return above or equal to the minimum HP threshold.