Lich Transformation 1 Boon: Harvesyer of Souls

You have gained the ability to tear the soul out of creatures you kill and consume it for its invigorating effects. Whenever you reduce a creature to 0 hit points, if you are on the same plane of existence as your phylactery, its soul is captured and your phylactery becomes charged. On your turn, as an action, you can consume any number of charge levels from your phylactery to regain a spell slot. When you regain a spell slot this way, the spell slot's level is equal to one-third of the charge you consumed, rounded down.