Frostbrood

The Frostbrood are elite frost wyrms raised from the bones of blue dragons at Sindragosa's Fall. They consist of whelps, drakes (vanquishers), and the mighty wyrms themselves. The Scourge raised a few ancient and powerful proto-dragons to become members of the brood as well.

After the Lich King awoke from his long dormancy, he journeyed to Sindragosa's Fall where he raised the ancient dragon Sindragosa, the first consort to Malygos, as a frost wyrm. His final desecration of Sindragosa was to tear the spirits of her lost whelps into undeath in front of her skeletal form, as a final affront to the great dragon, and then ordered her to lead the Frostbrood into war.

Later during the conflict, Sindragosa retreated to her lair in the Frostwing Halls of Icecrown Citadel, where she continued to strengthen her brood with the help of Ymirheim's vrykul. She defended the Lich King until the adventurers who went on to slay him destroyed her as well, leaving only her skull behind.