The Red Book of Westmarch records how some among the Orcs of Rhovanion came into the Battle of Five Armies mounted on the backs of the Wolves that were called Wargs. These Orcs were named Wolf-riders by Elves and Men and formed the cavalry of the Orc legions.

But this alliance of Orc and Wolf was not newly formed in that Age, for both Wolves and Orcs were bred by the evil hand of Morgoth in the Ages of Stars.

The histories of Beleriand in the last Age of Stars tell how the Sindarin Elves of Beleriand fought the Wolf-riders.

In the War of the Ring, the wizard Saruman had taken some into his service.