The OrksThe Orks are...well, they're orky. They're a mean, green, fighting machine that live for bigger and better brawls.
A little bit of history...Orks aren't really a race to keep track of themselves, but there isn't any need for it. To be simple, the Orks have been doing the same thing since they originated: stompin' and lootin'. If you are familiar with any other fictional orks or orcs, these are pretty much it. The universal idea of these races is the same; they are all crude, bloodthirsty dudes with some serious fungal issues. The Orks from the 40K universe have some interesting twists to make them more interesting, and way more hilarious.
On the subject of fungal issues, the Orks are wacky. Apparently, they have a symbiotic relationship with...algae. This is what makes their skin green, but is also what flows in their blood. Because of this, Orks aren't born, they're hatched from algae pods released when an Ork dies or a pod reproduces. They emerge from the pod fully formed Orks, ready for bashing in some skulls. The pod people also have a pretty sweet Wolverine style healing system because of their best bro algae. In fact, an Ork head can live for a while by itself, and can even be reattached to a different body, and leave the Ork a little shaken but overall okay. Pretty cool. Since they've got the regeneration on point, they pretty much just throw themselves into the fray and don't give a shit.
The Orks don't have a real structure, but instead have different clans on their various planets. Actually, hold up, gotta explain something quick. You might ask, seeing some of the pictures, how the Orks have, like, guns. And armor. And trukks (as they refer to them). If you've ever heard of the expression 'held together by spit and prayers', that's how all Ork technology works. In the lore, their tech is literally held together by the firm belief by all of the orks THAT IT WORKS. They think it works so hard that it actually does. Most of the time, it doesn't work well, but they're too busy fighting to really care. Anyways, the structure. Orks are led by the bigger orks. Simple as that. Whoever is the biggest rules the other orks. This is their belief about how life should be in the galaxy, and so that's why they're out trying to murder everyone to show them what's up.
One other important part of the Ork kultur (as they call it) is actually critical to their race. It is known as WAAAAUGH! This phenomenon is when a Warlord or Warboss starts leading a group of orks (usually a rather large group) to battle. As they crusade, after many victories, their bloodlust is made psychically manifest. This psychic howl, the utter rage and thirst for battle is known as the WAAAUGH!, and propels the orks further into their cause, and once a WAAUGH! has built up enough power behind it, it is very difficult to stop. In general, orks live for the WAAUGH!, and can't wait to get into the fight.
Overall, the Orks are a simple race. They just want to fight whatever they get their hands on.