Death Field

You draw the life force from every creature in a 30-foot cube centered on a point you choose within range. Each creature in that area must make a Constitution saving throw. A creature takes 10d8 necrotic damage on a failed save, or half as much damage on a successful one. If you reduce a hostile creature to 0 hit points, you gain temporary hit points equal to half the damage dealt. This power has no effect on droids or constructs.