Hmm agreed unless they were in some sort of hibernation or in hiding beneath the planet, the developers said that some of the strangest environments will be in the underground zones perhaps they were referring to more than tyranid hives and at some point in the game they awaken. I like to imagine all four factions facing off in a climatic battle at the end of the campaign when suddenly outta nowhere a new challenger enters the field and begin a devastating blitzkrieg that the four faction have to resist and counter attack not necessarily allied but fighting in the same general direction. And who says they have to be primitive technology takes many different direction and perhaps they have some dangerous warp technology of their own and acquiring this alientech is the reason why so many major players in the galaxy are so interested in this otherwise useless ball of dirt. the imperium wants to study and create counter measure to it, the chaos forces want to utilize it for the glory of the dark gods, the Eldar want to keep it out of the hands of the lesser races, and the Orks just showed up cause every oder Git was headed dat way. It was also kinda explain how the tyranids got there, according to the new tyranid post no hive fleet is recorded to visit arkhona but, due to the way tyranids and the shadow of the warp works most of the time the imperium isn't aware a hive visited a place until after its been nom nom nomed and left a ball of dust but in this case the aliens on the planet managed to partially fight off the tyranids destroying the hive ships but were unable to wipe out the swarms already on their world and fled underground, and so the planet survived with no one the wiser.
Alwayz wanted ta stomp dem Rak-gols, Loxatl, Exodite Eldar, Lacrymole shapeshifters, Jokaeros, Umbra, Demiurg, Tarellians dog soldiers, n dem runty Hurd.
I think there are more than enough Xenos in the 40k universe that we've never seen (for shame). I would strongly prefer to give them some screentime before we bother with introducing new ones.
Careful, man. You shouldn't talk about Squats. From what I heard, GW has this center that they use to monitor communications, and when they hear mention of Squats, they send out these super secret teams of agents who
