“Da Orks nevva loses. If we win, we wins. If we die, we dies fightin’ so it don’t count as losin’. If we runs fer it, we don’t lose neitha, ‘cos we can come back for annuver go!”
– Ghazghkull Mag Uruk Thraka

Brutish and green-skinned, Orks tribes exist on a million worlds. War-like, savage, and crude, orks are the most successful species in the whole galaxy, out-numbering all other intelligent species, even Mankind (with the very plausible exception of the Tyranids.)
Muscle-bound and always thirsting for violence, Orks live only for war. Whether fighting against the Imperium, other xenos, or other Orks, they simply do not care. Orks do not waste time pondering why or how to do things better, they simply act. Ork instinct and ability driving them on in a never-ending cycle of violence and conquest.
The distinct Ork culture (or “kultur” as the Orks call it) by and large it functions very well. Perhaps because the fundamental tenet of their society, simple so even the most pea-brained Snotling understands, claims “might makes right.”
Despite their ferocity and crude but effective technology, Orks rarely unite, preferring to fight among themselves in endless wars for dominance. This fractricidal tendency keeps Orks from overwhelming the Imperium.
When they do gather into a single-minded battle force, whole systems fall before the furious assaults known as a Waaagh! These alien invasions have wiped out whole regiments in their advance, men and women fed to the beast to slow or stop its assault. Such is the duty of the Imperial Guard.