Consume Soul

You attempt to rip the soul from a creature you can see within range. The target must make a Constitution saving throw. On a failed save, it takes 10d6 necrotic damage, and you gain temporary hit points equal to half the amount of necrotic damage dealt. If this reduces the target to 0 hit points, you capture its soul, preventing it from being resurrected by anything short of a Wish spell.

At Higher Levels: When you cast this spell using a spell slot of 7th level or higher, the necrotic damage increases by 1d6 for each slot level above 6th.