Amulet of Fire Breath

After putting this amulet on, the wearer cannot take it off. The wearer gains immunity to fire damage. The wearer exhales fire in a 30-foot cone. Each creature in that area must make a DC 14 Dexterity saving throw, taking 27 (10d6) fire damage on a failed save, or half as much damage on a successfulThe user must roll 1d20 + proficiency modifier at sundown of a 15  to use it again the next day or be charmed by Tiamat. 

Notes: Immunity: Fire, Dragonborn, Damage, Buff, Combat, Cursed, Jewelry