Editing Shattered Imperium (section)

===Xenos Collaboration===
Loyalists are slightly more open to xenos than the original Imperium of Man, primarily because they only had a few legions and lacked the numbers to truly defend their space without some negotiation with xenos. Their primary alliances are with the various factions of Craftworld Eldar, but as with the Imperium Secundus, conflict does erupt from time to time.

Chaos is pretty much chaos from our timeline. The exception being that the Dark Eldar never interact with them, as the legions are fully devoted to Chaos, lacking the renegades who just use chaos for their own means (Like Fabius Bile or the Night Lords.) 

Free Legions generally view xenos as a stepping stone for their objectives. While they will not hesitate to exterminate races that are enslaving humans, they will gladly ally with minor xenos races if it means gaining an advantage.

The Ascensionists are more than willing to utilize xenos knowledge and technology, but tend to view xenos allies as a weakness that will lead to the collapse of the path. So some haemonculi might be tolerated to modify marines and the Iron Hands descendants might study Necron tech but you won't generally see PoA fighting alongside Necrons or Eldar.

Renegades vary. Space Wolves probably kill them all, Lion doesn't care as long as they kneel before him, Guilliman is more willing to utilize xenos as auxiliaries for his armies.