Henchmen Race

As everyone knows, Villains have henchmen, but some aren't content with recruiting from the existing races and decide to make their own. The result is this trope, a race or species of beings that were created for the sole purpose of acting as troops for their creator, who for some reason is generally the bad guy, although there might be a non evil example out there somewhere. The degree to which the Henchmen Race is 'purpose built' can vary somewhat, ranging from the 'customization' of an existing race to making one from scratch.

May lead to Exclusively Evil, depending on the work.

Examples of Henchmen Race include:

Anime and Manga

Bleach has the Arrancar, which were artificially created from Hollows.
Originally, the Abh from Crest of the Stars were this. They are now at war with descendants of their creators.
The Zentradi of Super Dimension Fortress Macross and sequels had been created by Protoculture as giant warriors to police their space and to fight an unidentified threath (possibly the Vajra). Wary of the threath of a Zentradi rebellion, Protoculture implanted them a directive of not attacking the human-sized Protoculture members, that came to bite them in the ass when the experiment to create a more powerful Henchmen Race went horribly wrong, becoming the Protodeviln and started raising an army of mind-controlled Protocultures that the Zentradi were unable to fight. To contain the threath, the free members of Protoculture deactivated the directive. That bit them back in the ass too: the Zentradi used their numerical superiority to wipe out the enemy army and allow the Protoculture to seal away the Protodeviln, but then rebelled and destroyed their masters before they could reactivate the directive that kept them under control.

Comic Books

Darkseid's Parademons in DC Comics. Whether they're created as they are or modified from "normal" citizens of Apokolips (or some of each), they're superstrong, tough, nearly feral, and obey Darkseid's orders without question. Only two or three have exibited an individual identity or the ability to speak.
Skrulls are often used by non-Skrulls as mooks. Then again, even when the Skrulls attack on their own, the entire race seem to be nothing but a lot of mooks to be kicked around by the heroes.
The Mole Man from Fantastic Four has a race of Toad Men to do his bidding. They usually just hop around and serve as cannon fodder until the Mole Man uses his much-more formidable giant monsters.
Also from Marvel Comics: The Inhumans. They are a race of super-beings created several centuries ago by the Kree in order to have an army of super soldiers. Things didn't work out as planned since the colony decided to have nothing to do with them, initially. In fact, the Inhuman royal family is now lording over the entire Kree Empire, making this an inversion, if nothing else.

Film

Clone Troopers in Star Wars. They're obviously genetically members of an existing race, but they were specifically manufactured as soldiers, maturing at an accelerated rate and made genetically inclined to be docile and obey orders (probably including "ignore orders from the enemy").
- Many races from Star Wars Expanded Universe have origins of serving this function for the Rakata. The Noghri however regain the hat after the decline of the Precursors after Darth Vader tricks them back into this roles until Leia uses her status as heir to release them.
- The Arkanians, a race of Mad Scientists, genetically engineered various sub-species of their own race, generally referred to as "Arkanian Offshoots," as servants. They had a distinctly different appearance than baseline Arkanians, and were treated somewhere between second-class citizens and vermin.
- Ever wondered why the Hutts have the Nikto, Klatooinians, and Vodrans amongst them? They're all vassal races of the Hutts.
The Lord of the Rings films have the Orcs. Neither Saruman or Sauron are orcs but that doesn't stop them from using them for their armies. Saruman even created his own species of Orcs.
- That said, the orcs seemingly use trolls to this effect as well.
Koreans in Goldfinger. Auric likes them because they are "the cruelest people on Earth." Yeah...

Literature

In Garth Nix's Keys to the Kingdom series, The Piper creates the New Nithlings in order to be his servants and army.
The Orcs of The Lord of the Rings were created by Morgoth from corrupted Elves. Saruman took these Orcs and did something to them (probably crossbreeding them with Men) to make them less ineffective during the daytime.
- It's revealed in Unseen Academicals that the Evil Emperor of Überwald did the same thing except he just used humans--although most people think he used goblins. It's also revealed the orcs were driven into battle by men with whips--which Glenda points out means you can't judge them as Exclusively Evil based on that.
The Howlers from the Animorphs books are a particuarly interesting example since instead of the usual blind obedience or aggression, their creator made them so that they had almost child-like minds and thought that fighting and killing was a game.
- The Hork-Bajir are a variation on the customization variant, since they were turned into a henchman race by being made into controllers.
- And the Taxxons, who voluntarily became a henchman race.
The various shadowspawn from The Wheel of Time were created by Aginor to serve the Dark One and the Forsaken. Most, such as the Trollocs and Myrdraal, do so without problems- others, like the Gholam, are much more dangerous and difficult to control.
Young Uplifted species from the Uplift series. Client races are indentured to their Patrons for 100,000 years or more. They can also be treated (badly) as traditional Henchmen, including being used as cannon fodder. Some semi-legal species are specially made as weapons. Non-evil examples from the 'good' Patrons. Neo-chimpanzees are an entire species that must obey Humans. At the same time we treat them as much as equals as much as is permitted.
The Sranc from The Second Apocalypse were bred by the Inchoroi to form the bulk of their army.

Live-Action TV

The Jaffa out of Stargate SG-1 are examples of the 'take an existing race and modify it' variety.
Doctor Who has had some like these, most notably the Ogrons, who have been mooks of the Daleks and The Master. Even the Daleks, though not completely original, were created by Davros by heavily mutating and converting an existing race, the Kaleds, in order to fight under him.
- The Daleks themselves had a race of ~~manbearpigs~~ pig slaves under their command in Manhattan.
Jem'Hadar and Vorta in Star Trek: Deep Space 9 were this. Though according to The Other Wiki the Vorta to a lesser degree as they were an existing race that were genetically engineered by The Founders where as the Jem'Hadar were made from scratch.
- Word of God says that the Jem'Hadar were an existing race as well, though this was never made explicit on the series.
Rita of the original Power Rangers series had minions she had to create on her own, known as Putties. Later seasons gave us the Tengas, the Piranhatrons, the Sting Wingers, Batlings, Putrids, Kelzacks, Tyrannodrones, Hidiacs/Styxoids, Lava Lizards, Chillers, and Moogers/Spitfangs.
The Golem soldiers from Kyoryu Sentai Zyuranger.

Tabletop Games

In Planescape, as stated in The Other Wiki, "The Tanar'ri are a race of numerous demons originally created by the Exclusively Evil Obyriths as slaves."
Technically speaking, every existing species in Exalted was intended as this (although it was most overt for the Dragon Kings to the gods and the Jadeborn to Autochthon), and the Exalted have a few of their own as well (the Solars engineered numerous races, and the Lunars typically breed beastmen). Primordials/Yozis have the most direct examples in their First Circle Devas/Demons (custom made spiritual servitor races, in contrast to the Second and Third Circles, who are their patrons' literal souls).
The hat of the Old Ones of Warhammer 40,000 is this. Of course, every time it backfired horribly: to fight the Necrons and their masters C'tan, the Old Ones created various psychically-gifted races (including the Eldar) to exploit their enemies weakness against the power of the Immaterium, succeeding in driving them back but with the collateral effect of twisting the Immaterium into the Warp and unleashing the Enslaver Plague on the galaxy; to fight the Enslaver Plague, they created the Orkz, a Proud Warrior Race that loves fighting for fighting's sake that fought off the Enslavers with enormous collateral damage. It's not clear if the Slann are what remains of the Old Ones or another Henchmen Race of theirs, but in both cases the Old Ones are not that important anymore.

Video Games

Technically speaking this is more or less the point of a King Mook, for example Bowser leads the Koopas and Goombas (bar the good ones). Often though the Mook King is more of a general overall in the villain's army.
Sligs from the Oddworld series. They're essentially the same as their bosses, the Glukkons, only less enterprising. Unlike some of the examples of this trope, they're completely unsympathetic, as they are shown to be totally sadistic, conniving jerks. They're also examples of the 'modification' variety, since they weren't created by the Glukkons, but they were outfitted with legs and guns by them.
In Arcanum, it's implied that half-ogres were bred for this purpose by gnomes, but then it's revealed that it's all fake- or not, it got confusing.
- They were. You can even find breeding facility. But you just can't prove anything.
The obscure strategy game O.R.B as this as a major plot point. The two playable races were created by a Precursors race and they're at war because they believes the other destroyed their creators.
The Reapers in the Mass Effect series have the Keepers and the Collectors. The former were kept as docile as possible to keep their Artifact of Doom In Working Order without attracting attention, while the latter were highly genetically modified to serve as general muscle.
- Though the Keepers are no longer slaves of the Reapers, thanks to the Protheans.
  - The Keepers no longer respond to the Reaper trigger command, but in all other ways they remain non-sentient slaves to their Reaper programming. They still aren't exactly emancipated.
Halo some of the Covenant races roles are this, such as the Grunts, the Jackals, the Elites, and the Brutes.
Overlord has the Minions who serve the Evil Overlord protagonist as either frontline fighters (Browns), ranged specialists (Reds), assassins (Greens) or medics (Blues). They'll also take care of any grunt work needed.

Web Comics

This is SOP for many Sparks in the Girl Genius 'verse, particularly those well-disposed towards biology. (Those more inclined towards metalworking may settle for an army of Clanks instead.) The most notable example is, of course, the Jagerkin, created as fanatical and nigh-unstoppable footsoldiers by the old Heterodynes... the fact that they're still around today, and prospering despite the absence of their masters, is testament to their impressive engineering...
The "ghouls" from Sluggy Freelance were these for Leono, an alien who bred them by sleeping with random women. Because "asexual reproduction is for wussies!"

Western Animation

The Instant Martians employed by Marvin the Martian.
The Minions from Despicable Me. While the film hinted that Gru might have created them, the 2015 Minions film revealed them to be a separate species from humans that evolved in parallel, needing to serve whatever was the biggest, nastiest creature around.

Real Life

Possible Real Life example: Dogs. Studies have shown that it only takes about ten generations to turn a wolf into a dog. With an average breeding age of a year and a half, that's only fifteen years to get a dog.
- The Soviets domesticated the silver fox in less than fifty years, but it helps they knew what they were doing and had the ability to restrain the undomesticated generations. Lacking either of those, the original dog domestication probably took quite a while longer.