Cleansing Flame of the Hallow

A blinding streak of Divinity flashes from your pointing finger to a point you choose within range and then blossoms with a low roar into an explosion of Holy flame. Each creature in a 20-foot-radius sphere centered on that point must make a Dexterity saving throw. Fiends, undead and any target associated with Umbras Circle has disadvantage. A target takes 8d6 fire damage on a failed save, or half as much damage on a successful one. 

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the damage increases by 1d6 for each slot level above 3rd.