Armor of Asmodeus

*Ash and cinder flit around you, you glow with spectral fire and the temperature around you in a 10ft. radius increases by a couple degrees*
A protective magical force that seems to be gifted by the demon Asmodeus himself, surrounds you. The armor manifests as a spectral fire that covers you and your gear. You gain 10 temporary hit points for the duration. If a creature hits you with a melee attack while you have these hit points, the creature takes 5 fire damage.

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, both the temporary hit points and the fire damage increase by 10 for each slot.