Breath of the Fire Lord

A blast of superheated air erupts from your open mouth. Each creature in a 60-foot cone must make a Constitution saving throw. A creature takes 6d6 fire damage and is on fire 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 6th level or higher, the damage increases by 1d6 for each slot level above 5th.