Touch of Asmodeus

Your demonic expertise allows you to enchant your weapon with hell flames that saps the life of your enemies. This lasts for your next three turns and only works on melee armaments. Whenever you attack an enemy with a weapon enchanted by this spell they must succeed a con 14 saving throw or take 2d6 fire damage and heal you for 2d4. On a successful save the target takes no extra fire damage and you only take half the healing. 

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the extra fire damage increases by 1d6 and the healing by 1d4 for each slot level above 3rd.