Irkens

The Irkens are an imperialistic (and formerly xenophobic) race of green-skinned humanoids from the planet Irk, an M-class planet. The basic goal of the Irken race was and to some still is total universal conquest; they mostly attained this feat with the aid of their vast armada, which aids in planetary destruction via a sort of final attack called the Organic Sweep. This final attack is now initiated only for non-sentient beings such as amoebas, but used to be a procedure when the Irkens saw no use for their sentient conquered opposition, before Tallest Mius and his empress Talandra, decided to make the conquered races become servants instead, which unfortunately devolved into flat-out slavery when they were deposed.

One of the major powers of the galaxy and pretty much the entire observable universe, the Irkens are a proud people who value pride, tradition, war and combat. The aggressive Irken culture has made them an interstellar military power to be respected and feared.

Methods of Conquering
The Irkens implemented the Organic Sweep after one of their own, an Irken Invader, has successfully infiltrated and taken over or sabotaged a planet they intended 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 were 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 was to become a parking structure planet, but after Red and Purple were overthrown those plans were quickly abandoned in favor of an intergalactic video arcade and shopping mall. General Kratoz however is an expection to this, as he prefers to simply destroy and obliterate the planets instead of conquering them.

Irken Society
Irken society is best described as a hierarchy based solely on height (proceriarchy); tall individuals are respected and usually assigned to high-ranking jobs. Short individuals, on the other hand, were looked down upon both figuratively and literally (until a few changes were put in place by Zim when he ascended the throne), and were usually assigned to menial labor. The tallest living Irken (or Irkens) is selected to rule the Irken Empire (later: Irken Republic) as the Almighty Tallest.

The rest of the universe that know of the Irkens considered them to be bloodthirsty, tyrannical and dictatorial, which may be true to an extent. However, the Almighty Tallest and the Control Brains determined what the Irken population thinks through PAK programming. Considering Irkens bloodthirsty and tyrannical was therefore a matter of perspective, because Irken thoughts were actually mostly pre-programmed. Despite this, they do have a brain capable of independent thought. Kratoz on the other was bloodthirsty by choice (as a result of Tallest Miyuki's death), rather than programed as he sadisticly commited several atrocities that even the Tallest came to fear his brutality and savage nature. Irkens did 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.

Zim was an Irken Defective before he created the PAK-removal procedure; due to the "forty schmillion" errors in his PAK, he was not programmed like the other Irkens, but since even he was still extremely militaristic and feels a need to conquer, it is logical to assume the general Irken mindset was focused on universal domination.

Before Zim ascended to power and initiated several societal and political changes, Irkens were born via DNA vats deep under Irk's surface, and the Irken PAK is installed seconds after. A baby Irken, or smeet, then got 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 were not permitted on Irk's surface.