Literature / The Four Horsemen Universe
How Puny Humans evened the odds.
The Four Horsemen Universe is a Military Science-Fiction Shared Universe set in a world dominated by Private Military Contractors, led by American authors Chris Kennedy and Mark Wandrey.

In the early 21nd century, First Contact didn't go so well for humans, at least initially. The MinSha glassed the Middle East in retaliation for terrorist attacks on alien visitors, and Earth turned out to have little of worth to the races of the Union, besides people. Even that was touch-and-go, as humans are possibly the least physically imposing spacefaring species in the known galaxy (except the Flatars), so when humans tried to break into the highly competitive mercenary business they proved little more than Cannon Fodder. Only four companies out of the first wave of 100 to leave Earth to take what became known as the Alpha Contracts actually returned home, obscenely wealthy by Earth standards but dragging many caskets behind them. By sheer coincidence these four companies, Cartwright's Cavaliers, Asbaran Solutions, the Golden Horde, and the Winged Hussars, all used horse cavalry in their insignia, and hence became known as "the Four Horsemen".

Then Dr. P. Mauser, an engineer at Mitsubishi, developed the CASPer, a weaponized steel shell that let humans take the galaxy by storm... or at least even the odds enough that battles with alien mercs weren't so one-sided anymore. The technology continued to improve, and a hundred years on, CASPers have become the Weapon of Choice among human mercs, and the mercs themselves are highly sought-after for wars of all kinds.

Books in the series:

    The Revelations Cycle (Main Series) 
The first four books of the series form a single modified anthology, with each novel focusing on a single company after which the book is named, but serving an overall plot.
  1. Cartwright's Cavaliers (Wandrey, 2016): Bankrupted by his mother's financial shenanigans after the death of his father, Jim Cartwright, an overweight computer geek who flunked out of his mercenary aptitude tests, is forced to take control of the family company and rebuild it from the leavings of his forebears. Meanwhile, a major fluorine-11 find by an alien consortium attracts attention of the unfriendliest kind.
  2. Asbaran Solutions (Kennedy, 2017): A series of botched missions guarding a red diamond mine on the planet Moorhouse kills disinherited wastrel Nigel Asbaran's father and brother in quick succession and results in his sister being taken hostage. Asbaran must pull together whatever forces he can in a hurry to mount a rescue operation and regain the contract long enough to complete it.
  3. Winged Hussars (Wandrey, 2017): The Winged Hussars, the richest of Earth's mercenaries and the only human company to specialize in space combat, is under attack, and Commander Alexis Cromwell is forced to fight her way out of trap after trap in order to make it back to base.
  4. The Golden Horde (Kennedy, 2017): Following the attacks on the other three Horsemen, two things are clear to Golden Horde company president Sansar Enkh: that someone is trying to bring down Earth's mercenary industry, and that they're next. Her only choice is to try to spring the trap and unveil the attacker.

Following the conclusion of the Four Horsemen series, a new series picks up.
  1. Peacemaker (Kevin Ikenberry, 2017): The Peacemakers Guild are the closest thing the nebulous and weak Union has to Space Police, enforcing its laws and mediating disputes. Jessica Francis is trying to become the first human to join the Peacemakers, but before she'll be allowed to, she'll have to defuse a potential planetary civil war.
  2. Sinclair's Scorpions (Paul Corcoran, 2018, unreleased)

    Short Story Collections 
While creating The Revelations Cycle, Wandrey and Kennedy solicited side stories from a number of authors. They got so many responses they ended up having to make three different anthologies.
  1. A Fistful of Credits: Stories from the Four Horsemen Universe (2017): Foreword by Charles E Gannon. Stories:
  2. For a Few Credits More: More Stories from the Four Horsemen Universe (2017): Foreword by David Weber. Stories:
  3. The Good, the Bad, and the Merc: Even More Stories from the Four Horsemen Universe (2017): Foreword by David Drake. Stories:

Tropes in the Four Horsemen Universe:

  • Action Girl: A CASPer works equally well for either sex, so while it's not as common for human women to become mercs as men, they still appear widely. A woman is as effective commanding a spaceship as a man, too, as Alexis Cromwell, commander of the Winged Hussars, attests.
  • Altum Videtur: "Velut Luna" is Latin for "Like the Moon".
  • Ape Shall Never Kill Ape: It's rare but not unheard-of for two human mercenary companies to be hired by opposing sides (one such incident happens in "Hero of Styx"). The Four Horsemen have a gentlemen's agreement not to take contracts where they'd possibly fight each other.
  • Bittersweet Ending: Asbaran Solutions. Nigel Asbaran retakes Moorhouse from the Blood Drinkers (wiping them out to a man) and completes its contract, sparing his company from bankruptcy and disgrace. However, they and the White Company have taken heavy casualties, and Nigel's sister Parisa is killed by her captors before she can be rescued.
  • Blood Knight: Tortantulas love to fight, and being Giant Spiders with grasping hands and thorax-mounted eyes that give them incredible peripheral vision, are extremely good at it. They often pair up with Flatars, which ride saddle on the Tortantula into battle.
  • Boring, but Practical: Mark 8 CASPers are the state of the art, but Mark 7s are still in common use and perfectly serviceable for companies that can't afford Mark 8s. They're also less cramped inside than the Mark 8.
  • Cannot Tell a Lie: Tortantulas can't lie due to being Literal-Minded, and as such can suffer Blunt Metaphors Trauma and sometimes need to rely on their Flatar partners to keep them out of trouble.
  • Career-Ending Injury: The Winged Hussars have a Tortantula-Flatar pair, Oort and Jeejee, among their Space Marines. Jeejee explains to Alexis Cromwell that Oort lost part of a leg on a contract. It's not crippling but no Tortantula merc unit will hire a maimed one (probably because Tortantulas are Explosive Breeders and there's therefore no market pressure). Jeejee ran across her on a station afterwards and kept her from getting into the wrong prize-fighting ring; they joined the Hussars later.
  • Cowboy Episode: "The Last Guardsman" has a revolver-packing Bounty Hunter with a cowboy hat go on a hunt for an alien Serial Killer.
  • Fictional Geneva Conventions: There are some laws of war in the setting, but the Union is more an idea and a guild system than an actual government and they're very poorly enforced. The most inviolate rule, the one that will guarantee retaliation if you're caught, is that you're not allowed to use Orbital Bombardment: you may only launch air attacks from below an arbitrary ten-mile limit. Besquith mercs are shown to have violated this rule in Asbaran Solutions, but the protagonists don't have enough evidence to get the Mercenary Guild's enforcement arm involved.
  • Foreign Language Title: "Vvremya" is Russian for "in time". The protagonists spend 97 years objective on a planet orbiting a black hole but only think they've been down there a few weeks.
  • Grey Goo: The protagonist of "The Last Guardsman" is mortally wounded with a nanite-carrying bullet that eats him alive from the inside out.
  • Guy in Back: A Tortantula's Flatar partner acts somewhat like secondary armament on a warship, covering its six while the spider acts like a living tank, as well as helping the Tortantula to deal with personal interactions.
  • Heel–Face Door-Slam: The conclusion of "Angels and Aliens", sort of. Jim Hawkins, a Catholic chaplain, is held at gunpoint by a Tortantula and Flatar and reasons that, death being apparently inevitable, he'd rather spend his last moments praying. This actually interests the Literal-Minded Tortantula, who is curious to hear about Jesus. The Flatar is only interested in killing him, but merc Charlotte Wicza is faster and kills both aliens.
  • Humongous Mecha: The Raknars that Jim Cartwright accepts as partial payment on a contract are hundred-foot-tall robots designed by Precursors to kill canavars, genetically engineered monsters that devastated The Federation in a war ending in its collapse millennia before.
  • Intelligent Gerbil: A common form of alien in The 'Verse.
    • The Besquith are a man-sized wolf/wolverine/bear mashup with attitudes to match, and are the primary bad guys in the first two books.
    • Flatars resemble one-foot chipmunks.
    • Tortantulas are Giant Spiders with an extra ring of eyes around their thoraxes.
    • MinSha are man-sized praying mantises.
    • Oogar are giant purple bears.
  • Interfaith Smoothie: "Unto the Last—Stand Fast" has a syncretic religion resulting from cultural exchange between Roman Catholic human colonists and Crystal Dragon Jesus Arritim colonists (they had inadvertently both colonized the same planet, fought over it, and then ended their war when they noticed the similarities in their religions). Both groups' home churches consider this faith heretical, and the Arritims' progenitors the Arezzo (same species, different church) are engaged in a crusade against it.
  • It's Raining Men: CASPers have jump jets that among other things let them do paratrooper attacks without needing actual parachutes.
  • Literal-Minded: Tortantulas. As such they don't understand humor or metaphors, can't lie, and are relatively easy to take advantage of. Part of the job of a Tortantula's Flatar partner is to keep the spider out of trouble off-duty.
  • Loads and Loads of Races: According to exposition there are a few thousand species in the Union. Of those, 37 species work as mercenaries and a few hundred more tend to hire them. The first two books of the main series alone name humans, Besquith, Veetanho, Zuul, MinSha, GenSha, Jivool, Flatars, Tortantulas, Jehas, Cochkala, Pendals, Duplato, and Fey. The short stories add Arezzo (and their subculture Arritim), K'Kng, Oogar, and Avaka.
  • Mini-Mecha: "CASPer" is an acronym that stands for "Combat Assault System, Personal". Manned by a single crew member who has to take a nanite treatment to help heal from falls, it can equip an assortment of weapons including antipersonnel lasers, chainguns, MAC guns, and shoulder-mounted missile launchers. CASPers also have Jump Jet Packs that let them leap tall buildings in a single bound or make paradrops without needing parachutes.
  • Neutron Bomb: Banshee bombs. Built by Besquith mercs, they're illegal due to being designed to be detonated at high altitude, as in above the legal 10-mile limit for air attacks. When detonated, they kill every living thing across a wide area; the Besquith themselves are more resistant than other species to the radioactive contamination they leave behind. The Blood Drinkers used them to take the planet Moorhouse, and a lucrative garrison contract, from Asbaran Solutions, but Nigel Asbaran can't prove it and so goes on a Roaring Rampage of Revenge.
  • No Blood for Phlebotinum: A number of plots deal with fights over mines for rare mineral resources, ranging from uranium to red diamonds (used to back the value of the Union's currency) to the ultra-rare unobtainium fluorine-11 (a fuel used in fusion reactors).
  • Odd Friendship: On a species level between Tortantulas and Flatars. Flatar mercs will often ride Tortantula mercs into battle and act like a Guy in Back. The odd part is that, being two-foot-tall chipmunk-looking things, the Flatars look more like something the Giant Spider Tortantula would be having for dinner.
  • One-Product Planet: Entire species are often known as mercenary races, partly because only 37 of the thousands known work as mercs. Earth's government in particular is known to get most of its income from taxes on merc profits, in exchange for which it provides training and recruitment services in its schools.
  • Orbital Bombardment: One of the few hard-and-fast laws of war in the series is that this is illegal: you may only fire weapons at a planetary surface from ten miles' altitude or below. In Asbaran Solutions the protagonists discover that the Besquith have been covertly breaking this law: the Blood Drinkers took Moorhouse by using radiation bombs dropped from high altitude.
  • Outgrown Such Silly Superstitions: Downplayed. Religion itself isn't dead, but "Angels and Aliens" mentions that organized religion hasn't done well following First Contact. The viewpoint character is a scion of a mercenary family who became a Catholic priest and joins the Berzerkers as a chaplain, to find that much of the membership are neo-pagans of various stripes.
  • Private Military Contractors: The focus of the series.
  • Puny Earthlings: Of the 37 mercenary species, about the only one less imposing than an unarmored human is a Flatar. The first CASPers were constructed to even the odds.
  • Raised by Wolves: The viewpoint character of "Lessons" (a lemur-like alien of a species that appears in several of Kacey Ezell's stories) is left to die in the wilderness as an infant and is taken in and raised by another intelligent (non-tool-using) species on the world, finally returning to her people as an adult and forming a tribe of her own.
  • Rags to Riches: Earth as a whole, at least by galactic standards. Poland sold off its entire strategic reserve of natural resources and its nuclear arsenal to fund the Winged Hussars for the Alpha Contracts, who are now richer than the GDP of entire Earth nation-states. The world government taxes mercenary profits to provide a living stipend to citizens.
  • Roaring Rampage of Revenge:
    • In the backstory, the MinSha reacted to terrorist attacks on aliens by glassing much of the Middle East, including most of Iran (where the Asbaran family is from).
    • Nigel Asbaran versus the Besquith Blood Drinkers mercs in Asbaran Solutions. Justified: after they kill his father and brother and take his sister hostag, ehe strikes their base on the Besquith homeworld to gather intelligence, but also wipes out their home guard and nukes the place to get revenge. He then enlists the White Company to help him wipe out the rest of the Blood Drinkers on Moorhouse.
  • Tanks, but No Tanks: In-Universe example in Asbaran Solutions when the mercs complain that the Jeha engineers they've hired can't tell the difference between a tank and an armored personnel carrier.
  • 'Tis Only a Bullet in the Brain: While defending the freighter Coronado from pirate boarders in Winged Hussars, Rick Culper is shot in the head with a laser at close range. Thanks to the ship's autodoc he survives, barely, though he suffers some long-term memory loss and damage to his amygdala that leaves his emotions almost nonexistent (which makes him literally fearless in combat).
  • Twenty Minutes In The Future: By Word of God [1], First Contact happened between Earth and aliens in the 2020s. The series proper takes place in the 22nd century, per the blurbs on the Short Story collections.
  • Ungovernable Galaxy: In theory there's a galactic Union that provides some measure of law and order, a successor state to The Federation which collapsed thousands of years ago. In practice the Union is little more than a weak guild system and wars over planets and resources are near-constant. In Winged Hussars Alexis once wryly remarks to herself that this nigh-on anarcho-libertarianism isn't the best form of government the Union could have picked, it's just the only one that works even this well.
  • Unobtainium: Fluorine-11 (usually just called F11), a fictionalnote  rare isotope of fluorine that is necessary for fusion reactors and therefore extremely valuable. It is only found amid supernova remnants, former gas giants whose atmosphere has blown away, and the accretion discs of black holes.
  • Uplifted Animal: Any species with the suffix "-Sha" in its name is the result of an uplifts.
  • Vehicular Turnabout: Twice in Asbaran Solutions, Nigel steals Blood Drinkers ships and uses them to get close enough to attack the enemy mercs on the ground.
  • Whole Plot Reference: "Unto the Last—Stand Fast" is a Fantasy Conflict Counterpart of the Stand of the Swiss Guard by way of Sabaton's song about the battle, "The Last Stand", even using lyrics from the chorus as a Trust Password.
  • Year Outside, Hour Inside: In "Vvremya", once they're told they're mining a planet in close orbit around a black hole, a Line in the Sand is drawn: those who don't want to take the risk of not being able to climb back out of the gravity well are allowed to stay behind in a shuttle stocked from the expedition supplies, to be picked up once the expedition has mined the valuable deposit of F11. The expedition leaders fail to account for Time Dilation, and while only a few weeks pass for the miners, on the shuttle 97 years go by and everyone aboard starves to death.