The Mord Wraiths are a fictional organization from the Shannara series by Terry Brooks. They were human sorcerors in service to the Warlock Lord who recovered and were subverted by the Ildatch.
Mord Wraith, a Gnome term for Black Walker, was given to these successors of the Skull Bearers. The Mord Wraiths were feared throughout the lands for tales of their power: men's minds destroyed, bodies blackened by fire, and the ability to move without a trace. The Mord Wraiths reneged on an ancient pact between their former master Brona and the Mwellrets of the Ravenshorn Mountains and attacked them with a magical contagion, before driving them from Fortress Graymark and establishing their rule in their stead. They were served by the former Mountain Gnome slaves of the Mwellrets, as well as by a range of sorcerous monsters they created or summoned using the Ildatch. The Mord Wraiths then attacked the Dwarven realm, and the health and essence of the Four Lands itself through poisoning the source of the Silver River at Heaven's Well. The only opposition to them was the Druid Allanon, who tried and failed to penetrate the Maelmord they had created around the Ildatch (Wishsong of Shannara)
The Mord Wraiths continued to pursue and deter the efforts of Brin Ohmsford and Jair Ohmsford. However, they were destroyed when the Ildatch disintegrated.
The Mord Wraiths had the appearance of tall ebony skeletons in black cloaks whose magic appeared in the form of red fire. At times they carried staffs of burnished witch wood, such as when they summoned a Kraken at Capaal. The Mord Wraiths were invulnerable to non-magical damage.