“Xenos” is a term used to refer to alien races that are not human – often used by the Imperium of Man to describe alien races that are seen as a threat or as being inferior to humans.

While Xenos may include many different alien races, such as the Aeldari, the Orks, or the coalitions that make up the T’au Empire, there are still hundreds of other species known to lurk the stars. These include fauna from Death Worlds, carnivorous flora, and horrors sentient or otherworldly.

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The dark forest hypothesis

  • Many alien civilizations exist in the galaxy, but are silent and paranoid because any space-faring civilization would be an inevitable threat.  As a result, Xenos may view the stars as a “dark forest” filled with armed hunters stalking through the trees, each ready to slay the other in a form of self-defense. To survive, Xenos must make their presence invisible, and when there are exterminatus-level weapons in the hands of tyrants and madmen, this is probably a pretty good strategy to follow.


  • The avian-like Kroot have a lot in common with ancient tribal customs in Humanity. Individual Kroot may be driven by a desire to improve their own abilities and the strength of their clans through the process of devouring, as well as a desire to earn wealth and power through their mercenary work. They may also be motivated by a desire to protect their own interests and those of their clans.