Cold wraith

Cold wraiths are multiple types of undead in service to the Scourge.

Road to Damnation
Cold wraiths are wraiths that have a cloudy, translucent form with a frigid malice in their glowing eyes. When Kel'Thuzad tried to escape from Naxxramas, in Northrend, after seeing its horrors, a group of cold wraiths spoke to him saying that he could not escape and even if he did escape no one would believe his story. Instead of fighting or fleeing, Kel'Thuzad decided to cooperate and become the apprentice to the Lich King and "with enough training, he could surpass the necromancer or catch the man off guard." The wraiths teleported Kel'thuzad inside the citadel, they led him into a cavern with stairs, the Icecrown Citadel, where they began to ascend. At the top, he found an ice block instead of a necromancer, it was the Lich King. One of the wraiths pushed him so that he could advance, the Lich King told Kel'thuzad that he wanted to scour the humanity from Azeroth and the wraiths didn't let Kel'thuzad to leave. The Lich King told him that he could choose between immortality or an unbearable pain, then the cold wraiths leave the room and Kel'thuzad decided to serve to the Lich King.

''It is unknown if they were "cold wraiths" or just normal "wraiths" that were cold. They are only referred to as "cold wraiths" once. Also, they are closer to shades than wraiths.''

Warcraft III
In a pre-beta version of Warcraft III: Reign of Chaos, a unit named Undead Cold Wraith was intended to be a playable and a buildable Undead Scourge unit, but it got scrapped before the game's release. It was like a grim reaper unit with a dark cape and scythe.

Their description was as such: "The few surviving Warlocks who were captured along with Ner'zhul by the Legion were transformed into spectral apparitions of living cold. Renamed Cold Wraiths, the damned spirits became twisted and evil. Filled with the desire to inflict pain and suffering, these former magic users now serve their Lich King without question and use their newfound necromantic powers in his name. Cold Wraiths can fly across any battlefield and rain down their terrible bolts of cold-fire."

Abilities

 * Chill Touch - Slows target unit.
 * Lifetap - Takes life from target unit.

World of Warcraft


Cold Wraiths could be found in the Ruins of Andorhal prior to patch 1.4.

This mob is similar to the ones seen in "Road to Damnation".

Wrath of the Lich King
Coldwraiths, a type of skeletal mage, can be found in Acherus: The Ebon Hold. The model name of these creatures is "cold wraith". It is possible that this advanced type of skeletal mage is actually called a "cold wraith" in an overall sense. Concept art indicates that at some point they were a unique type of creature that resembles a cross between a wraith and a skeletal mage.

Clattering Coldwraiths and Wrathbone Coldwraiths, also skeletal mages, were added later.