|Known characters|| Zim|
The Irkens are an imperialistic race of green-skinned humanoids from the planet Irk. The basic goal of the Irken race is total universal conquest; they mostly attain this feat with the aid of their vast armada, which aids in planetary destruction via a sort of final attack called the Organic Sweep.
Methods of Conquering
The Irkens implement the Organic Sweep after one of their own, an Irken Invader, has successfully infiltrated and taken over a planet they intend to conquer and has learned of its main weaknesses. When the intelligent inhabitants of the planet have succumbed to Irken persuasion, they are forced to work as slaves; non-sapient inhabitants are simply killed off. The planet is then given a single purpose: For example, Foodcourtia became an intergalactic food court, the planet Vort became Irk's top military research prison, and Blorch became a parking structure planet.
Irken society is best described as a hierarchy based solely on height; tall individuals are respected and usually assigned to high-ranking jobs. Short individuals, on the other hand, are looked down upon both figuratively and literally, and are usually assigned to menial labor. The tallest living Irken (or Irkens) is selected to rule the Irken Empire as the Almighty Tallest. The rest of the universe that know of the Irkens consider them to be bloodthirsty, tyrannical and dictatorial, which may be true to an extent. However, the Almighty Tallest and the Control Brains determine what the Irken population thinks through PAK programming. Considering Irkens bloodthirsty and tyrannical is therefore a matter of perspective, because Irken thoughts are actually pre-programmed. Despite this, they do have a brain capable of independent thought. Irkens do not seem to sleep (see footnote on Irken Biology), though it is not known why; even though, on occasion, they have been shown to be capable of sleep and dreaming.
Invader Zim is an Irken Defective; due to the "forty schmillion" errors in his PAK, he is not programmed like the other Irkens, but since even he is still extremely militaristic and feels a need to conquer, it is logical to assume the general Irken mindset is focused on universal domination.
Irkens are born via DNA vats deep under Irk's surface, and the Irken PAK is installed seconds after. A baby Irken, or smeet, then gets all existing knowledge in the Irken database downloaded into his/her brain and then immediately reports for duty. Until they are of age, however, young Irkens are not permitted on Irk's surface.