The K-Series were a genetically engineered breed of Xenomorphs created by the scientist Dr. Samuel Kadinsky. They were designed to be superior, but whenever the races went head to head, the original strain won out every time.



After the Weyland-Yutani Corporation acquired several Xenomorph specimens, the head scientist of the project began genetically manipulating the creatures in order to create a suitable bio-weapon. This became known as the K-Series which were visibly different from the standard breed due to its yellow skin tone.

Initial tests of the newly developed K-Series forced the creatures to fight a small brood of standard Xenomorphs but the original strain proved superior in the battle. The K-Series would continue to survive but an attack on the research facility by the Predators caused a breach in containment resulting in the K-Series being freed. A Queen was created which continued laying more Eggs for the species to develop.


The parent strain and the K-Series were antagonistic to one another with the original breed seeking to exterminate the divergent species in order to maintain racial purity. After a long battle against the Colonial Marines, Predators and a Xenomorph Hive; the K-Series Aliens would be exterminated bringing a quick end to the race. (Aliens versus Predator: Extinction).


These "K-series" Aliens behaved like normal Xenomorphs as they gathered hosts and had a queen that affected the hive. They also had all the same castes as the normal xenomorphs though with a different color.


  • The K-Series likely stands for "Kadinsky Series"
  • The Original strain of aliens considered this unnaturally occurring strain a racial impurity and instinctively sought to wipe it out.
  • The Red Xenomorphs are another strain of differently-colored aliens, although these are the product of natural mutation.



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