[sabredog]

Dan Abnett's Commissar Gaunt series , Ciaphas Cain by Sandy Mitchell and the Ultramarines series by Graham McNeill are my favourites.

I find some of the books far too gothic and dark for my taste. I enjoy the tabletop game though, having played it for many years.

Forget the power of technology and science, for so much has been forgotten, never to be re-learned. Forget the promise of progress and understanding, for in the grim dark future there is only war. There is no peace amongst the stars, only an eternity of carnage and slaughter, and the laughter of thirsting gods.

Warhammer 40,000, known informally as "Warhammer 40K" or just plain "40K", is a miniatures-based tabletop strategy game by Games Workshop. Drawing heavily on their previous Warhammer Fantasy game, it began as "Warhammer In Space", but has over time grown distinct from (and much more popular than) its counterpart.

What makes 40K unique in the gaming genre is its extreme darkness. Set thirty-eight thousand years in the future, the game's basic premise, insofar as it can be summed up, is that of an eternal, impossibly vast conflict between several absurdly powerful genocidal, xenocidal, and (in at least one case) omnicidal factions, with every single weapon, ideology, and creative piece of nastiness imaginable turned Up to Eleven. As a result, the galaxy has been twisted into a hellish morass of horrors that rival even the foulest and most disturbing Lovecraftian monstrosities.

The central faction, the Imperium of Man, once held immeasurable glory, but is now a fascist theocracy whose messiah has been locked up on life support for the past ten millennia, laid low by his most beloved son. An incomprehensibly vast Church Militant commits horrible atrocities in his name on an almost-daily basis. Millions of capricious, fanatical, genetically engineered Super Soldier Knights Templar and equally fanatical, pyromaniacal battle nuns serve as the Imperium's special forces, while its trillions-strong regular army takes disregard for human life to new and interesting extremes. A futuristic Inquisition ruthlessly hunts down anyone with even the slightest taint of the heretic, the mutant, or the alien, to the point of authorizing the destruction of entire planets. Technology has, at best, hardly progressed for twenty thousand years, is largely considered magical because the science behind it has been long forgotten, and the deranged machine cult that preserves and replicates what remains of it considers innovation to be blasphemy against the wisdom of the ancients. The Warp, the Faster-than-Light Travel the Imperium must rely on, carries with it a good chance of being raped by daemons, and the Astronomican, the navigation aid used to negotiate Warpspace, is powered by the God Emperor's soul and has the souls of one thousand psychic humans sacrificed to it every day, dying by inches to feed the machine.

The problem is, as bad as the Imperium is, it's not quite as bad as many of the other factions; dying when facing them is about the best fate you can hope for. The ancient and mysterious manipulator race, hovering near extinction, contrives wars that see billions dead so that small handfuls of their own may survive, while their depraved cousins must spend their lives perpetuating mass slaughter and Cold-Blooded Torture to stave off their own destruction. Vast Bug Swarms are trying to eat every organic thing in the galaxy as part of their natural life cycles. An entire civilization of incredibly advanced, undying, living metal conquerors are awakening after millions of years of slumber, ready to reclaim a galaxy they see as rightfully theirs. A genetically-engineered warrior species infests every corner of the galaxy and is cheerfully trying to kill everything else (including each other, if nothing better presents itself) because it's literally hard-wired into their genetic code to do so... and because it's fun. The closest thing to the "good guys" you can find in this setting is a tiny alien empire sandwiched between all the other factions, and they may or may not have a thing for forcing new subjects into their empire through orbital bombardment, concentration camps, and possible mind control by a few benevolent elites... but at least they'll offer you admittance into their club before doing any of that stuff. Many of these factions have a common foe in the forces of Chaos, which infests the Warp, exists to corrupt all it touches, and is best known for two light-years-wide holes in reality through which countless daemons and corrupted daemon-powered super-soldiers periodically attempt to bring the universe to further ruin.