The Ork Menace is a great one. For every Imperial citizen, there are roughly 40 Orks out in the universe. They control about 80% of the known universe. But what keeps them from outright destroying the Imperium is this sole fact: they love to fight. They love to fight so much, that they don’t care if it’s with themselves, leaving the entire race utterly disorganized. There are many different clans; many times a system will have a different clan on each planet, or multiple clans on the same planet. But as they love to fight and can never seem to compromise, they rarely ever organize an attack.
Physiologically, Orks are one of the toughest sentient creatures in the universe. They range from 1.75 to 3.5 meters in height and have a very bulky build, almost looking like they are constantly hunched over. Their skin comes in many shades of green, though environmental effects could change it. They have large protruding jaws with long, tusk-like teeth. They have the intelligence of a small child, though some can show some remarkable aptitude in mechanics. Generally, their leaders are either the strongest of the group, or the most cunning, being able to make promises and sound strong to keep control.
Occasionally, one of these very cunning Orks decides that he would be better off somewhere else than amongst his home band. They would then take a small craft of their own and fly off towards some other place. Many times, this ends up being an Imperial system. And on most occasions the craft would be taken out in space and not a second thought would be given. But sometimes they may fly themselves towards the more forward thinking systems. Here, they would be met with a strange glance, but if he would prove himself a resource, and aid to the Imperium in some way, he could be given admittance to live and work amongst the peoples of the Imperium.