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This information is ambiguously canon and has not been confirmed to be canon.
The Red Xenomorphs, referred by the Humans as Red Aliens. are a rare 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 their red color of their skin.
After the first Queen Mother was captured, the xenomorph homeworld begin to fall into complete and utter chaos. While a Warrior was morphing into a new Queen Mother to take the original's place, several deviant Drones designated as "Red Drones" by the humans were born and rebelled against the primary hive. Soon after countering a hive consisting of the Red Drones led by the Red Queen Mother, a massive warfare begun between the two subspecies over the genetic abnormalities. A fleet 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 crew decided to decimate the Red Mother's hive to distract the Drones of the original nest while the jelly was being extracted.