Warp

ALL THE CRAZY SHIT GOES DOWN HERE

If you're not a Chaos god or at least a Greater Demon, you probably have no business being here. Which of course means that all the sapient races of the galaxy flock to the Warp (or the Immaterium) like boy scouts to a knot-tying badge, except for the Tau (who are only just discovering the horrors awaiting them here) and the Necrons (Which haet it).

Warp travel is used to speed everything up so it doesn't take for ever to get to places. Unfortunately, the Imperium of Man has shitty protection against it, and effectively plays a game of Russian roulette in hopes that they wouldn't get them selves killed speeding towards where ever