Warg-riders

Warg-riders were a group of Orcs specially trained to ride Wargs into battle.
== History ==
Warg-riders first appeared during the Battle of Five Armies, where they killed many Men and Dwarves before being defeated on the slopes of the Lonely Mountain. Based on descriptions in The Hobbit, the Orcs of the Misty Mountains had some control over the Wargs living there. However, most Warg-riders were loyal to the evil leaders of Mordor.
Azog and Bolg, as well as many orcs under their command, are shown to ride Wargs as they pursue Thorin and Company, and later take part in the Battle of the Five Armies. 
Saruman sends out Warg-riders under the command of invented character Sharku to attack the people of Edoras, as they travel to Helm's Deep.
The Orc lieutenant Gothmog rides a Warg, but only for transportation. Two Warg-riders are seen riding alongside the Easterlings after the Olog-hai breach Minas Tirith's main gate.
Warg-riders' armor are distinct from that of other Orcs. Some, such as their leader (allegedly named Sharku) wore little beyond bone and fur, whereas others preferred to be more heavily protected, wearing multiple layers of rotting hide, fur and hair or mail, but nearly all included something from the remains of the Warg's kill, such as bone and tooth, and from parts of the Warg itself. Keeping their weight down was a factor with most in order not to tire the Warg.
Their cuirass was often made from the bones of a horse's rib cage, to which was stitched pieces of hide and fur; during centuries of wear — if the Orc survived his close contact with the Wargs, living with and feeding them as they did — the Warg-rider's armor would go from foul-smelling to rotten, and so would need to be constantly repaired and replaced.
Fresh hide would be stitched on top of old, and bones would be replaced as they disintegrated. Other parts of the orc's body would be wrapped in hide that had been reinforced with bone, and adorned with Warg fangs and spikes made from sharpened bone, to protect it from both enemy and ally.
Their armor may have been further strengthened by bonding pieces together with glue made by boiling down horse bones and hooves. Some orcs wore helmets made from the skulls and scalps of their kills, both beasts and men, and these often featured grisly crests of bone. A rough cloak of Warg fur would have completed the outfit.