Ork Boyz are about 2 metres (6'6") tall when standing fully upright and vary greatly in their specific battlefield roles. Ork Boyz who occupy the same field of interest often band together in groups known as Mobs, frequently these mobs are led by an Ork Nob who epitomises the group's skills. As basic Ork troops, Ork Boys vary in weaponry and equipment. They are usually divided into the following categories.

Note that Ork Boy can fall into several categories, for example, if he is equipped with Shoota, 'Eavy Armour and Stikkbomms and rides into battle on a Trukk he would be a Shoota Boy, a Stikk Bomma, 'Ard Boy and Trukkboy at the same time.

The Orks, also called Greenskins, are a savage, warlike, green-skinned race of humanoids who are spread all across the Milky Way Galaxy. They share many features with Warhammer Fantasy Orcs (and were initially called "Space Orcs" to distinguish them). They are seen by their enemies (pretty much everyone else in the universe) as savage, warlike, and crude, but they are the most successful species in the whole galaxy, outnumbering possibly every other intelligent race, even Mankind (with the very plausible exception of the Tyranids).

Greenskins are one of the most dangerous alien races to plague the galaxy. Numerous beyond belief and driven always to fight and conquer, the Orks threaten every single intelligent species of the galaxy. Orks are possibly the most warlike aliens in the 41st Millennium, and their number is beyond counting. Amid constant, seething tides of war and bloodshed, burgeoning Ork stellar empires rise and fall. Mercifully most are short-lived, soon destroying themselves in a maelstrom of violence and internecine conflict, but should the Orks ever truly unify, they would crush all opposition.

The Orks' unquenchable thirst for battle has always proved their downfall: historically, the Ork tribes have spent much of their time fighting amongst themselves, waging brutal wars with only the strongest surviving. On occasion, an Ork leader will emerge who is mighty enough to defeat his rivals and unite the warring tribes. His success draws other tribes to him, and soon a great WAAAGH! is underway -- partly a migration, partly a holy war that can exterminate the populations of entire star systems. When the Orks are on the rampage, the galaxy trembles, and in these dark days of the End Time, there are more WAAAGH!s rising than ever before recorded.