The Red Xenomorphs, referred by the Humans as Red Aliens are a mutated Xenomorph breed that rebelled against the primary xenomorph hive on their homeworld and created their own colony, dubbed the "Red Army".
The Red Xenomorphs take on the normal characteristics of a normal Xenomorph, with the exception of the violently red shade of their skin.
After the first Queen Mother was killed during the Earth War, the Xenomorph's hiveworld begin to fall into complete and utter chaos due to their leader's absence. The Queen Mother's remaining Elite Guards together decided to form a cocoon in order to produce a new Queen Mother to restore order within the hiveworld. Several deviant guards also created their own cocoon, which eventually molted into the Red Queen. The Red Queen Mother started to breed her own red-colored Drones and soon rebelled against the original hive. A massive warfare begun between the two subspecies over the dominance of their species. Meanwhile, a platoon of Colonial Marines were sent to the hiveworld to retrieve the Queen Mother's prized jelly in order to synthesize a highly addictive drug called Xeno-Zip. The Colonial Marines unintentionally became involved in the war once they have landed on the hiveworld and had to fight off both of the Alien types, suffering massive casualties in the conflict. The remaining crew decided to decimate the Red Queen Mother's hive to distract the Drones of the original hive while the jelly was being extracted. With the Red Queen Mother gone, the remaining Red Aliens were soon wiped out by the original hive.
- The warfare between the Red Aliens and the regular Aliens is somewhat similar to that of the fighting between red ants and black ants.