Blazing Slash

As a part of the action used to cast this spell, you must make a melee weapon attack against one creature or location within the spells range. A crescent of energy races from the attack, and each creature in a flat 30 foot cone (oriented as you choose) in the direction of the target must succeed on a dexterity saving throw. A creature that was hit by the weapon attack automatically fails the saving throw. On a failed save, a target takes 4d6 fire damage and has its defenses undercut, causing attacks against it to have advantage until the end of your next turn. The crescent leaves a 6-inch deep gash in any non-magical objects or terrain it contacts, cleaving entirely through lesser width. A creature that succeeds on its saving throw takes half as much damage and doesn't have its defenses undercut.

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.