Helegrogs

Among the oldest Servants of Morgoth were Beings of the eternal ice as cold as their Master himself.These were the Helegrogath (S. "Demons of Ice"), enormous, blue, icy-winged creatures surrounded by an aura of blue-white flame. They were typically armed with icy blue spears, which they wielded two-handed. Lesser than Balrogs, the Helegrogs were demons of cold fire used as wardens in the lands North of Thangorodrim. Alhough many were crushed in the devastation caused by the fall of the Dragon Ancalagon, some survivors fled to the far North. Few Helegrogs were ambitious, so they made little kindoms for themselves in the far North of Middle-earth, subjugating Snow-trolls and Snow-Orcs unfortunate enough to be ensnared in the frozen desolation, ruling their domains as living gods known as the 'Troll-Kings.