Here are some quotes from the Inquisition from the WK40 universe, because why not:

"Some may question your right to destroy ten billion people. Those who understand realise that you have no right to let them live!" - In Exterminatus Extremis

"I carry with me an Inquisitorial Seal. It is a small, unassuming object contained in a neat box of Pluvian obsidian. It is a modest thing. Relatively plain, adorned with a single motif and a simple motto. Yet with this little object I can sign the death warrant of an entire world and consign a billion souls to Oblivion." - Inquisitor Fazael

"There is no such thing as a plea of innocence in my court. A plea of innocence is guilty of wasting my time. Guilty." - Inquisitor Lord Fyodor Karamazov

Here is a quote about Genestealers:
"I don't know where they come from. It seems highly unlikely that they evolved naturally into what they are now - impossible, given what we know about evolution. Perhaps they are some kind of bioweapon, created millennia ago by madmen for some long-forgotten war. If so, I suspect that their creators soon came to regret their creation. Or perhaps they come straight from the warp. Possibly the Lords of Chaos themselves cast them out because they were too unpleasant." - Jarv Advent, Senior Xenobiologist, Inquisitorial Institute of Proctos Minor

Qoutes for orks:

"Travellin' through space is boring. Well, boring unless da hulk yer on is full of dem gene-sneakers, or a base fer da chaos lads wiv da spikes, or already has Boyz on it. Or if humie lootas come callin', that's always good fer a bit a sport. Or unless yer have a mutiny or two to pass da time, or unless strange fings start happenin', which dey usually do when yer out in da warp. One time we had some bloody great ugly fing come straight out of Weird Lugwort's 'ed! It butchered half da lads, that was pretty entertainin'. Come ter fink of it, space is a pretty good larf. And that's before yer find yerself a nice world ta crush!" - Bigmaw, Ork Runtherd

"Wot's faster than a warbuggy, more killy than a warbike, and flies through da air like a bird? I got no bleedin' idea, but I'm gonna find out." - Kog da Flymek, pioneer of the Dethkopta