Orcs are a member-species of Mental's Horde, originating from Zorg altered by a mutagenic ooze.
In the hopes of restoring their lost skin, the Zorg started applying a mysterious green ooze. When it became apparent that the ooze was turning the Zorg into Orcs, they outlawed it and exiled the Orcs. They were later absorbed into Mental's armies. Despite their physical similarities to their Warcraft counterparts, Orcs exhibit a greater degree of technological development than expected from the barbaric connotations associated with their name, including energy weapons and aircraft (although this may have been partly provided by Mental).
In addition to their apparently militarised culture, Orcs seem to include sports as part of their culture, including football. In fact, one Orc football player was cloned repeatedly due to Mental's reported favour towards him.