Army of Thieves and Whores

"Taggart: What do you want me to do, sir? Hedley Lamarr: I want you to round up every vicious criminal and gunslinger in the west. Take this down. [Taggart looks for a pen and paper while Hedley talks] Hedley Lamarr: I want rustlers, cut throats, murderers, bounty hunters, desperados, mugs, pugs, thugs, nitwits, halfwits, dimwits, vipers, snipers, con men, Indian agents, Mexican bandits, muggers, buggerers, bushwhackers, hornswagglers, horse thieves, bull dykes, train robbers, bank robbers, ass-kickers, shit-kickers, and Methodists! Taggart: [finding pen and paper] Could you repeat that, sir?"

- Blazing Saddles

An army of thieves and whores is a military force made up of the lowliest dregs of society. There's slaves, beggars, prostitutes (and their kids), robbers, criminals, outcasts, renegades, carnies, backstabbers, and in general everybody you wouldn't expect to see in a proper army.

Generally, these guys will be the heroes, because Underdogs Never Lose. In most cases, they're some sort of rebel army opposing their imperial oppressors, who will of course be well-ordered, disciplined, and often respectable. There may also be a theme of uniting the downtrodden to stand against their oppressors.

The French Foreign Legion is often characterized this way, both in fiction and real life.

In Real Life, assembling them into a properly trained army had been a rather hard task not only for reasons of literacy or discipline, but also due to the spread of chronic disease in a population with poor or no access to medical care and proper feeding and living conditions. A recruit from the poorest class in the Victorian Age could be expected to have either latent tuberculosis, syphilis, gonorrhea, bone diseases, or, worse, all of them together, and in crowded military camps germs are easily spread. (The ordinary peasant recruit of the State army was not much healthier either.)

See also Ragtag Bunch of Misfits for a smaller-scale version. Contrast the Carnival of Killers.

Anime and Manga

 * The prisoners from the Impel Down escape in One Piece.
 * In Naruto, the Villain of the Week Zabuza is forced to team up with Naruto and company to take down an army of these after his employer betrays him.
 * The Black Dog Knights of Berserk were made up of the worst criminals of all of Midland. They were so bad that they were sent to a distant prison on the border of the kingdom for their war crimes.

Comic Books

 * The name comes from the rebel army raised against the tsar in Nikolai Dante, which does indeed consist mostly of robbers, prostitutes, pirates, and various people the tsars have trodden on.

Film

 * Norm MacDonald's character from Dirty Work at the end has a crack team assembled of senior citizens, homeless dudes, and "my loyal army of prostitutes", the latter two of which counted as a Chekhov's Gun each.
 * Hedley Lamarr organizes one of these for the climactic battle in Blazing Saddles. This is, as the page quote suggests, an evil version.
 * The slave army in Spartacus qualifies as this trope. In this case, however, the army loses.

Literature
"Phule: "It's been done before. Specifically the Devil's Brigade... the first Special Service force, which eventually became..." Beeker: "The Special Forces. Yes, I'm familiar with the unit. If I might point out, however, that was a joint U.S.-Canadian force. At the beginning, the Americans provided a motley assortment of rejects and criminals, as opposed to the Canadians, who donated a crack fighting unit. While you definitely have your allotment of criminals, I fear you're lacking the offsetting crack fighting unit to serve as an example.""
 * Gaius Marius' legion in Emperor: The Gates of Rome is viewed by the more conservative Romans due to Marius abolishing the land requirement for entry, bringing in numerous poor citizens who otherwise would have had no means of supporting themselves. And they love him for it. In the second book, Spartacus' slave army also qualifies.
 * Since Marius also appears the the Masters of Rome series, his legion fulfills a very similar role, and plays a key role in the first book.
 * Temujin's (Genghis Khan's) forces in Wolf of the Plains starts out as one of these, as he initially builds up his forces by recruiting the various outcasts and nomads who would otherwise have nobody to stand with.
 * The Night's Watch in A Song of Ice and Fire are like this; most of its members are criminals whose crimes were pardoned in return for joining, and many of the willing volunteers are misfits of some sort. Most people in Westeros consider service on the Wall to be essentially a glorified penal colony. After thousands of years without even seeing The Others they're supposed to defend the Wall from, the Night's Watch has become ridiculously underfunded, to the point that of the 19 forts in the Wall, they can barely man 3 of them by the time the story begins. In A Storm of Swords, some local prostitutes help the Night Watch fight off a Wildling onslaught, making this a quite literal example of the trope.
 * In one of the Spellsinger novels, the communist dragon Falameezar rallies the world's rats and mice to rise up against oppression.
 * In Un Lun Dun, Deeba's army of rebels starts with the... extreme shoppers, and works its way up from there.
 * Michael Moorcock's short story To Rescue Tanelorn. Narjhan raises an army of beggars from Nadsokor and leads them to attack the city of Tanelorn.
 * Phule's Company has the Omega Company. In the Space Legion in general asking about a recruit's past is a big taboo, and "Omega" is the unofficial "dumping ground" for commanders willing to get rid from recruits they deem unsuitable. Their own sergeant noted that the result "looks more like a schoolyard" and "separated the problem Legionnaires into two groups: the wimps and the hard cases". That is, either unable to function in an army (or society in general) or inveterate criminals. Then the protagonist business shark promoted to command this mob thought it's not as bad as it looks...


 * In Saga of Darren Shan, the vampeze get around their strict refusal to use projectile weapons by hiring human thugs and cutthroats. Debbie and Alice eventually come up with the idea for the vampires to join forces with humans for the same purpose. Those humans mostly end up being homeless people. It's justified because those are the people the vampeze are feeding off of, so they're only too happy to have a shot for revenge.
 * Much of the British Army in the Peninsula as seen in Sharpe—hence Wellington's quote below under Real Life.
 * Victoria's newborn army in Twilight. She basically turned whoever she could find. It doesn't work.
 * The army John brings to fight the Crusades in A Dirge for Prester John. They're the cream of Pentexore, but they have no idea how to form an actual army.

Live Action TV

 * The Bowzocks from Gekisou Sentai Carranger are pretty much the bad guys from Blazing Saddles In Space, being an army of alien criminals hired to depopulate the Earth to make way for a hyperspace highway.

Tabletop Games

 * Unsurprisingly, common in the Warhammer 40,000 universe.
 * The Lost and the Damned are a villainous (well, more villainous than usual) version - they make up various Chaos armies, and are composed of mutants, murderers, heretics, and assorted scum of the Empire.
 * The Imperial penal legions follow this trope straight, being armies primarily conscripted from the inmates of Imperial prisons. When the Planetary Defense Force contributions to the Imperial Guard from worlds that serve as incarceration centers, the line between "penal legion" and "Guardsmen" become indistinct.
 * Most Penal Legions are formed of people that are desperately trying to clear their records by volunteering instead of accepting execution; given that the PL are sent to some of the worst parts of the fighting and are considered expendable (even more so), this often ends in Redemption Equals Death.
 * It's worth noting that there is no shortage of capital crimes in the Imperium, so it's not uncommon for people to be eligible for induction into a Penal Legion for petty reasons.
 * Ostensibly non-Penal units may turn out to be no better. Most of the Imperial Guard is recruited from the Hive Worlds, simply because the hive cities have by far the greatest population (and population pressure). There, it's a fairly common practice to round up some underhive gangs and make them an offer they cannot refuse, to kill two bird with one stone (meet the quota and cull the criminals). Which is not discouraged, because such recruits at least already can fight, use cover and understand teamwork - which is more than can be said about e.g. random scribes and janitors picked by the lottery. They only have to be whipped into shape and taught some discipline. Which may have more implications than looting or the thriving army black market: did you read about the Commissars who get inadequately brutal with decent troops or find themselves out of their depth with crack troops? Their training was mostly intended to deal with the lowest common denominator - exactly because it's quite common.
 * Dungeons & Dragons adventure CM1 Test of the Warlords. The domain ruler Longtooth has "Longtooth's Legion", an army of 500 thieves armed with bows and swords.
 * Exalted has the Vermillion Legion-or, as it had every reason to be called, "The Red-Piss Legion". Had, as thanks to Lady of War Tepet Ejava, it's now a Badass Army. Which is a very good thing, as she's the nice candidate for the throne of the Realm.
 * The Capitol faction of Mutant Chronicles has two flavours. The traditional one is the Freedom Brigades, which consists of volunteers willing to trade ten years of brutal service in the solar system's worst hellholes for a clean rap sheet and Capitol citizenship. The other flavour is the Free Marines, Capitol's most famous special forces outfit. In order to be eligible for the Free Marines, you have to have served for at least two years in another special forces unit, been decorated for gallantry under fire at least three times, been recommended for promotion, and been sentenced to death by a court martial.

Video Games

 * The eponymous team of Team Fortress 2 consists of a hoodlum, a game hunter turned hitman, a pyromaniac, a crazed civilian who believes he's a soldier, a chain-smoking assassin, a saw-wielding quack with mad scientist tendencies, a drunken swordsman/explosives expert, a Russian boxer, and a shotgun-toting Texan with a robot arm.
 * The Player's army in every Fire Emblem game will be this by the end, though it also includes many nobles and trained soldiers as well. You will recruit anybody, despite their background, who even remotely dislikes the antagonists or is friends with someone already in your group.
 * In Assassin's Creed II Ezio assembles a (literal) army of thieves and whores (and mercenaries) to oppose Borgia rule, and in Assassin's Creed Brotherhood he adds an army of Assassins to the mix.
 * You can assemble one in Age of Empires III, either by hiring them from the Saloon building or summoning them as mercenary group. For some reason, they are more expensive than conventional army.
 * The Asian dynasties subvert this, by hiring the Repentant version of them from Monasteries. They aren't any better or any worse than the ones summoned from Saloon, though.
 * The main characters of Valkyria Chronicles III. The Nameless includes repeat arsonist, convicted murderer, brothel madame, con artist, draft-dodger, sadistic dominatrix, trigger-happy alcoholic, and money-grubbing mechanic. The leader is charged with treason. What a merry band of undesirables! This is just one of the many, many way the game is Darker and Edgier compared to its earlier installments.
 * The Umbrella Corporation has multiple mercenary units. The Umbrella Biohazard Countermeasure Service, first introduced in Resident Evil 3: Nemesis is comprised largely of convicts, including death row inmates. While their stated goal was to rescue personnel trapped in Raccoon City, it's revealed in-game that the real reason Umbrella sent them in was so they'd get slaughtered, allowing the corporation to evaluate the military applications of their various monsters.
 * Dragon Age has the Legion of the Dead, a dwarven army composed of anybody willing to give up every single aspect of their former lives in order to take up arms against the darkspawn. A funeral is held for every new member and in all ways save the obvious they are considered dead by society. Thus, if you're bankrupt, wanted, disgraced, insane or somehow otherwise unfit to live among normal people, you can join the Legion and be accepted and pardoned. And many do. Even non-dwarves can join if they wish (something absolutely unheard of anywhere else in dwarven society) because the Legion is chillingly aware it is a Redshirt Army-in-waiting and takes all the bodies it can get.
 * Even the Grey Wardens are less extreme in presentation but ultimately just as inclusive and binding. Anyone can be conscripted - from blood soaked psychopaths right out of the hangman's noose and the lowliest slaves to princes, kings and lords - and in particular apostate mages (who'd otherwise be executed, lobotomized or imprisoned) are free to fight right alongside everyone else. Their job is to stand between the darkspawn and the world, giving up everything (lives included) so the realm can exist in peace, and they are equally legendary and reviled for their heroism and absolute ruthlessness.
 * In StarCraft, approximately 50% of the enlisted in the armed forces of the Confederacy of Man/Terran Dominion are brainwashed criminals (running the gamut from thieves and murderers to the occasional political prisoner).
 * At one point in Neverwinter Nights 2, your character is given command of a unit of Greycloaks, Neverwinter's civilian militia. If you want, you can recruit new Greycloaks by offering amnesty to any criminals who'll join your forces.

Real Life

 * The British Army of the Napoleonic era. Almost entirely made up of the lowest orders of society anyway, convicted criminals made up perhaps a third of the manpower. Their commander in the Peninsular Wars, Sir Arthur Wellesley, described them as, "the scum of the Earth". Though he also added, "It is only wonderful that we should be able to make so much out of them". He was right - they overlapped with Badass Army.
 * "Convicted criminals" in Wellington's army, though, often included debtors, poachers, petty theives, and others whose crimes were either minor by modern standards or were commited because the perps were down on their luck. It is harder to estimate how many actually would have been hardened professional criminals.
 * The Argentinian navy in the 19th Century was something of this. In fact, because most of the convicts that comprised his crews wouldn't remember the sails names, but were experts at card games, Admiral Brown had the sails renamed to cards names.
 * The Dirlewanger Brigade of the Waffen-SS from World War 2. The unit was originally made up of poachers, but was ultimately ranked with any criminals or mental patients the SS could find. Even the rest of the SS was disgusted with them.
 * Though that said, their "disgust" was probably based not so much on their behavior as the fact that the brigade was made up of a large number of people who the SS would normally have gassed or shot. Their actions were heinous but "the rest of the SS" was up to genocide, so they were probably considered at worst a reflection of the kind of barbarity they would expect from such a bunch, rather than the other kind of professional and civilized barbarity practiced by themselves. Less a case of Even Evil Has Standards than an extreme example of Moral Myopia.
 * The "Ever Victorious Army", at least in its earliest incarnation. Formed in 1860 in Shanghai during the Taiping Rebellion, the initial force was recruited by Frederick Townsend Ward (and his backers) mainly from Europeans present in Shanghai, the "scum of the Shanghai docks": Beached sailors, mercenaries, criminals, deserters and expatriates. Those who survived and stuck around became the officer corps for an army of several thousand Chinese soldiers, and this army of dockside scum grew and evolved into possibly the most veteran, well-drilled, and tactically innovative fighting force of the period, first under Ward's leadership, and then under Charles George "Chinese" Gordon.
 * Before Sun Tzu earned his fame, he was given a test from the King: turn 180 concubines into a small army. He pulled it off, though he had to punish some of his officers before they would take him seriously.
 * The American Continental Army started out as this. It was made of people who didn't have any experience of warfare, who didn't have any strong officers who could inspire strong discipline among them, many of them deserted the "army" to go back to their families and farms and didn't return in weeks. It suffered from lack of food, uniforms and ammunition, bad language and diseases were infecting the army so hard that hardened Seven Years' War veterans were shocked by it, most of the soldiers only fought the revolution half-heartly, alcohol was consumed in great volumes, etc. It's said that when George Washington got to see the "army" he had accepted command of, he had a Heroic BSOD for half a hour before he started cleaning it up.