Cold-drakes (Q. "Helkaloki"; sing. "Helkaloke") comprised the most common and oldest breed of Dragon. All other Dragons were descended from their line. Bred by Morgoth as the ultimate fighting creatures, they were the first monsters to threaten the peace of Middle-earth.
There were four types of Cold-drakes: the True Cold-Drakes or Winged Cold-drakes (Q."Rámalóki"); and three wingless varieties: the Angûlóki or Cold-Worms, Ice-drakes, and their smaller cousins the Land Drakes.
True Cold-drakes were powerful, armored creatures whose scales were thicker than those of other Dragons. Agile but wingless, they had powerful limbs and long, steely claws. A Cold-drake's bite could crush a fully-armored foe, and a sweep of its whip-like tail could easily fell a Mûmak. They relished physical combat and were quick to strike when confronted. Cold-drakes enjoyed the hunt, but they loved the fight.
Most Cold-drakes lived in cold or frigid climes, preferring the wastes and alpine highlands to more temperate lands. These monsters were, after all, spawned in the utter cold of the Farthest North. Thus, they were stout, strong, immune to icy weather, and capable of smelling prey up to ten miles away (no Dragon possessed as great a sense of smell). Their coloring also reflected their affinity for the snows. Although they varied in hue like other Dragons, most were grey-white or even white in color. Still, the older, more powerful, Cold-drakes were often black, brown, or even red.