You attempt to separate the soul of a living creature from its body. Choose a creature you can see within range. The target must make a Wisdom saving throw. The target takes 6d6 necrotic damage on a failed save, or half as much damage on a successful one.  Additionally, if the saving throw failed by 5 or more, then roll 3d6: If the total equals or exceeds the target’s Constitution score, then the creature has vulnerability to the necrotic damage dealt by the spell. If the damage reduces a creature to 0 hit points and it failed the Wisdom saving throw, then the soul is forcibly separated from the body, killing the creature outright. The spell has no effect if the target is a construct, undead, or doesn't have a soul.

At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, the damage increases by 1d6 for each slot level above 4th.