Destructive Wrath

A release necrotic energy into the space in front of you. Each creature in a 15-foot Cone makes a Constitution saving throw, taking 2d8 necrotic damage on a failed save or half as much damage on a successful one.On a failed save, a creature takes an additional 1d8 necrotic damage at the end of its next turn.

Using a Higher-Level Spell Slot. The damage increases by 1d8 for each spell slot level above 1.