Orcs are a race of humanoids that will be Encountered in the Kasony Game. their Back story bears on the Larger Fringe worthy game.
Orcs are aproximately human sized. They tend to be more muscular, and have broader features than humans. Orcs have tusks.
The Ur-Orcs, naturally occuring beings are tribal people with a narrower "People" button than Humans, Elves, or even Dwarves. Their loyalty to tribe and suspicion of outsiders is strong enough to led them to reject ideas and technologies invented by outsiders.
Their hostility to outsiders leads to conflict with other sentients who encroach on their territory.
Note that this description is general - Orcs are individual beings, and any given Orc could be anywhere along a sliding scale or variation.
Extroverted Orcs, curious Orcs and Orcs who seek knowledge from outside Orc-Lore are more rare than comparable individuals of other races, but they do exist.
Orcs are a subspecies of human, evidenced by cross fertility. Mentioning this to the average Orc is to invited a beating or more murderous assault.
These people treat half-orcs born inside the tribe as tribe members, although ones tainted by "Outsider"-ness.
Garry Stahl Discussed Orcs here