The Imperial Guard is the collective military of normal humans and the military backbone of the Imperium in Warhammer 40,000. It has been said that if the Space Marines are the tip of the Imperium's spear, the Guard are the rest of the spearhead, the shaft and the man holding it. While often the designated victim in works featuring other forces, the Guard appears to have considerable success in the 41st millennium, as well as having a considerable favor with the fans.Besides the popular Gaunt's Ghosts and Ciaphas Cain series, they feature in Fifteen Hours, Death World and Rebel Winter (collected in the Imperial Guard omnibus), Steven Lyon's Ice Guard, Aaron Dembski-Bowden's Cadian Blood, Steve Parker's Gunheads, Desert Raiders, and Henry Zhou's Flesh and Iron, just to name a few. They also commonly appear in other Warhammer 40,000 works, such as Henry Zhou's The Emperor's Mercy, Graham McNeill's Storm of Iron, and The Last Chancers series. And in third quarter 2012, the guard will get their own game in the 40K roleplaying series: Only War.Not to be confused with Praetorian Guard,note (which is coincidentally also the name of Imperial Guard regiments from the planet Praetoria) which is the trope of imperial/elite guards as a whole.
Tropes connected with the Guard and the novels
Armchair Military: Many commanders, especially those part of a 'high command', are armchair generals. The 'garden variety' commonly resides within command vehicles such as a Leviathan. Alternatively they will command an HQ far behind the front.
Artistic License - Military: Depending on the Writer, the Guard may behave more or less realistically. A common problem is that the scale of the Guard's undertakings doesn't fit with the amount of people used. In a fluff blurb, a warmaster boasts that his crusade has half a million men and women under arms. Crusades usually encompass entire sectors of space, with at least a dozen earth-like worlds to be conquered. For reference, the axis powers in WW2 had about 35 million soldiers to conquer one planet and we all know how that one turned out.
Battle in the Center of the Mind: Mental battles with psykers/daemons or the simple mind scrubbing that war manages to do, usually to characters that have been in field longer than their psyches can handle.
A Tanith trooper, in the first few pages of First and Only, flips out and begins to shoot at vermin in his own trench. He is dealt with accordingly.
To elaborate: he is slated to be shot, but a Chaos attack interrupts the procedure, sparing him. He later display's cowardice during an action on Caligula, but ends up shot anyway.
Beam Spam: What Imperial Guard infantry generally seek to achieve.
Brass Balls: One common saying (in fanon) about the Imperial Guard (the Redshirt Army) is that on the first day, each recruit is handed a T-shirt (flak jacketnote Which is better, lighter, and more durable than anything we can dare hope to produce in the near future, fully capable of blocking (minus broken ribs) the damage from a direct hit from the equivalent of a modern heavy machinegun!), flashlight (a lasgun, one of the weakest possible weaponsnote in 40k, that means can "only" dismember an unarmored target on hit), and a wheelbarrow for their pair of giant steel balls.
Bug War: Typically Guard vs Tyranids. "Desert Raiders" is a Bug War with a twist.
Cannon Fodder: Quite obviously Penal Legionnaires and Conscripts.
Cloning Blues: The Death Korps of Krieg are all clones of the exact same guy.
Conscription: Patently Conscripts note The unit in the tabletop game, not the concept.. What else?
Well, there is mandatory service on worlds like Cadia.
The Kasrkin had a standout moment in the second Eisenhorn book. Totally dedicated badasses. The squad escorting Eisenhorn are surprised by a daemonhost, and the ones that die don't go down like Red Shirts.
In-universe, elite units like Storm Troopers or Kasrkin are often derided as "Glory Boys" and "Toy Soldiers" by the regular soldiery. The Kasrkin actually prove to be an exception, at least to the run-of-the-mill Cadian guardsmen serving with them, who recognize their superior abilities and look up to them.
Death Korps Grenadiers as well, more so than other Veterans, as they usually match the Kasrkins stated above (and are still viewed as cannon fodder, being the first ones charging the enemy).
Humongous Mecha: Titans, although strictly they are not part of the Imperial Guard, they are allies.
Interservice Rivalry: Most regiments hate the regiments from other planets. Particularly those from opposing class spectrums. Some veteran units invert this though and instead respect each other as competent warriors.
Land Battleship: Super heavy tanks and other vehicles such as the massive Capitol Imperialis, the huge Leviathan Command Vehicle and the staggering Ordinatus.
The Men First: Most good commanders have this attitude. Commissars - not so much.
It is noted as unusual, in universe, that Colonel-Commissar Gaunt and Commissar Cain are (relatively) humane commissars. In some cases the attitude is looked down upon by peers and superiors alike.
Commissar Viktor Hark, who joins up with Colonel-Commissar Gaunt's regiment, has an interesting moment when chastising another Guard unit that retreated in battle at a critical moment. He executes their commander rather than any of the men who followed him in retreat, saying that if their commander had held the line, his men would have done so as well.
Mildly Military: Depends on what planet you're from. Soldiers from Cadia or Mordia outright avert this, with strict adherence to rules and regulations. Catachans embody American GI's from the Vietnam War and have looser rules. Other regiments use this trop out of necessity, such as the Tanith First and Only, or come from their leader's tendencies, like Ciaphas Cain's regiment.
Rare Vehicles: Super-heavy class vehicles and Titans, but not quite so much a heavy emphasis on rarity in later editions.
Redshirt Army: A highly capable one, usually (at least in 5th edition).
Shoot The Fuel Tank: A distinct problem that Hellhounds used to have, what with the rear compartment housing some or all the fuel for its weapon and the sheer variety of weapons that can ignite fuel on contact.
Tanks, But No Tanks: The Leman Russ battle tank and its derivatives are the only true tanks available to the Guard, superheavies notwithstanding. The rest, primarily based on the Chimera chassis, are a mixture of APCs, IFVs, self-propelled guns and other assorted support vehicles.
Tank Goodness: The Imperial Guard takes this trope Up to Eleven, starting with the humble Chimera IFV, the Hellhound Flame Tank, and the ever-reliable Leman Russ Main Battle Tank, all the way up to the massive superheavy Baneblade. Just check out what Forgeworld cranks out. They had tanks coming out of every orifice for a year or two before slowing down again.
Took a Level in Badass: The Imperial Guard has been Flanderized as full of General Ripper type leaders who do nothing but human wave attacks against enemies, but recently, a number of novel series, particularly the Ciaphas Cain series and Gaunt's Ghosts series, have portrayed the Guard has a highly trained and sophisticated modern fighting force combining mechanized warfare, air support, and artillery strikes. Nevertheless, considering all the horrible stuff out there in the 40k universe, it's not always enough.
Urban Warfare: A common setting for the Imperial Guard, especially on (ex)Imperial worlds.
Walkie-Talkie Static: Happens on and off in the literature and now happens in the 5th edition if you botch an Order roll.
Zerg Rush: "Space Marines are the sword of the Emperor, making precision cuts and and stabs in the holes of the enemy's armor. The Imperial Guard are the sledgehammer." Like the above analogy, this explains probably the most common Imperial Guard tactic, in which you try to break the enemy by rushing them with overwhelming men, tanks, and artillery strikes in an attempt to flatten the entire area.
A good example of this, from The Armour of Contempt, is a mass charge, as in dozens of thousands of men, by Imperial Guard forces is seen from the ground, inside the rush, including supporting Titan firepower and Titans themselves.
There's also the Penal Legions. As punishment for sins against the Emperor, they are deployed with even less armor and weaker weaponry than the standard Guardsman to swamp the enemy with bodies, to clear minefields, and as a screen for tanks.