Evil Breath

summoning your demonic magic into your mouth then shooting a tiny red orb at a spot within range, the orb explodes into a small radius. Each creature in a 10-foot-radius Sphere centered on that point makes a Dexterity saving throw, taking 8d8 Fire damage on a failed save or half as much damage on a successful one.

Flammable objects in the area that aren’t being worn or carried start burning.

Using a Higher-Level Spell Slot. The damage increases by 1d6 for each spell slot level above 3.