Fire Demons (Q."Nauraukar" S."Norrogath") were fallen Ainur related to the element of fire. Many once had been servants of Aule, others had been among the host of Tulkas or Fire-Fays from the gardens of Vána or Nessa while still others had not been Maiar at all, but were corrupted Spirits of Arda.
Among the most powerful Fire-demons were the mighty Balrogath, other lesser fire Demons were the Rogmulath, Gorgonaurath, Red Demons, Fiery Grim, Fire-Phantoms or Devam and Marlthryg from the fiery Harad Deserts.