Irken

Several examples of Irkens.

An Irken Skeleton

The imperialistic, warlike Irken race is an insectoid species native to the

Irken written language

planet Irk and are feared throughout the universe for their goal of entire domination over everything by conquest which the Irkens are likely to succeed in due to the military superiority which has expanded the Irken Empire over many worlds. The Irkens latest military campaign, Operation Impending Doom 2, has been a great success with the conquering of Planet Blorch, the Conveyer Belt Planet, and Planet Vort, and the enslavement of the extremely intelligent Vortian race. The Irken Armada will keep the Empire expanding over many more planets marked for conquest to come.

Society and Culture

The Irkens have a height based society which the Tallest living Irken rules over as the Almighty Tallest. But on rare occasions there is two Tallests who are exactly the same height such as the case for the current Tallests, Tallests Red and Purple. Tall Irkens are respected and get high-ranking jobs while short Irkens get low paying jobs.

Irkens are born in cloning tubes in facilities known as the smeeteries deep under Irk's surface and can speak and walk when born due to them given the whole of Irken knowledge which is transferred after their PAK is installed moments before after they are greeted with a voice recording which says Welcome to life, Irken child. Report for duty.

The whole Irken mindset is fully focused on total domination of the universe as Irkens feel an urge-like need to counquer other worlds. This urge could actually all come from the Irken PAK.

Invader Zim OST - Suite from "The Nightmare Begins"

If not the Irkens themselves not acting out of free will to think for themselves, but at the same time this could not be the case considering that Zim is a defective with a damaged PAK and still feels a mighty need to conquer Earth.

Irkens seem to be capable of forming friendships similar to humans. It has also be stated by Jhonen Vazquez that Irkens do in fact have the ability to show love. However,what kind of love is not specified. It is possible that an Irken COULD form a romantic relationship with another Irken,but it is most likely very rare. Due to their society most likely not finding love important or beneficial, along with their loss of reproductive hormones and the ability to naturally reproduce. There are no canon examples of Irken love however.

PAK

The PAK is the key to an Irkens' knowledge and has an Irken's rank and career on it and can be changed by the Control Brains to a different rank or job. Also the PAKs take note of an Irken's success and high scores. The PAKs are equipped with robotic spider legs for combat. An Irken can't live without their PAK for more than ten minutes. Irkens do not have a biological need for PAKs while on Irk, rather they perish after exactly ten minutes because without their PAKs, Control Brains cannot control them. The PAK does, however, contain an atmospheric processor and translation software, allowing Irkens to breathe in atmospheres unlike that of Irk, and understand many languages other than Irken.

Biology

An Irken squeedly spooch.

It is possible Irkens have a single super-organ called a Squeedly Spooch which preforms most, if not all bodily functions.

Reproduction

Irkens are known to be produced through DNA merging in underground facilities many fans refer to as 'smeeteries' (a portmanteau of smeet and nursery). It is implied that since the discovery of this system, Irkens no longer use the ability to reproduce naturally, since Smeeteries are more efficient in perpetuating their race. No Irken is ever mentioned as having a mate or offspring in the show. (Jhonen confirmed in the commentary to Dibship Rising that the Irkens do in fact have the capability to show love.)

Trivia of Doom

• In Irken Conquest,there are a few examples of Irken romantic relationships. One of these being Menami and Zik, this is most likely because said irkens were exposed to Earth culture and became accustomed to it. (Excluding Entra and Averii,due to them being from an alternate universe)  Otherwise love is usually shown to be foreign and strange to the Irken race and its culture,and the few that know about it see it as repulsive. Despite this romantic love is not outlawed or prohibted, but is simply just seen as weird. However,inter-species relationships are mostly seen as disgusting, due to most Irkens being incredibly xenophobic. 
• Also in Irken Conquest it is shown that Irkens can be affected by physiological medicine despite their PAKs being essentially a cybernetic brain. They can also be intoxicated by alcoholic substances as well.