Blood Barrage

You not only drain your opponent's life force, you are able to revitalize your own health.

Choose one target you can see within range. The creature must succeed on a constitution saving throw or take 6d12 necrotic damage, or half as much on a successful save. On a failed save, the caster is healed for half the damage inflicted by the spell. 

When cast at 7th level or higher, the damage increases 1d12 per level.