Dawnbreaker cleave

Dawnbreaker Cleave: You call upon the raw power of the sun into your strike. When you cast this spell as an action you can make a melee attack that launches a wave of solar energy, this wave deals radiant or fire damage and travels in a 30 foot line. Any creatures in the wave's path must make a DEX save or take 2d8 damage, if they succeed the save they take half damage. When cast at higher levels the damage increases by 1d8.