Burning Servants

Effect: The caster summons a circle of flaming warriors that strike toward the center of the circle. These fiery warriors cannot harm the caster but will relentlessly attack anything else within their bounds. Targets inside the range must make a Dexterity saving throw. Receiving 3d8 fire damage on a failed save, or half as much damage on a successful one.

Using a Higher-Level Spell Slot. The damage increases by 1d8 and the area by 5 feets for each spell slot level above 1.