Abhuman

In the late 41st Millennium, Abhumans are those descendants of baseline human settlers who have mutated and evolved after being isolated on worlds across the galaxy with various extreme environmental conditions. The term may be short for "aberrant human", "abnormal human", or, less pejoratively, derived from the Latin term ab humanis, "from humans". In an Imperium of Man where genetic mutation and spiritual corruption are often viewed as interrelated, Abhumans are a focus of much controversy for the Imperial government. In more liberal times under the direct rule of the Emperor of Mankind during the Great Crusade, even markedly divergent Abhumans such as the Beastmen could serve in the Imperial Guard. Since the Emperor's stasis in the Golden Throne began, however, only the lesser Abhuman mutants, such as Ogryns and Ratlings, are allowed full citizenship in the Imperium. However, they are still distrusted by the Puritan members of the Inquisition.

Abhuman Game Usage
In the most recent editions of Warhammer 40,000, only the Ogryns and Ratling Snipers are mentioned in the main rulebook. However, in the American edition of White Dwarf 302, an official article was published featuring doctrines that allow Imperial Guard armies to take units of Abhumans, expanding on the Ratling Snipers and Ogryns of the core rulebook. The article featured Beastmen (or Homo sapiens variatus), Mutant Slave Levies (ordinary mutant slaves rounded up to serve as Imperial cannon fodder), Feral Ogryns (even nastier and more primitive creatures than regular "civilised" Ogryns), Nightsiders (mutants originating from worlds of perpetual or near-perpetual darkness, who have little to no ability to see but are the perfect warriors for night-fighting missions), Afriel Strain Soldiers (human clones genetically engineered from DNA taken from the greatest heroes of the Imperium, very unlucky and unpopular), Subs (relatively genetically stable but still hideously deformed mutant sub-breeds) and Gland Warriors (genetically-normal Imperial Guardsmen implanted with special organs and glands that secrete combat-useful chemicals, such as stims and pain-killers).

Navigators
A Navigator (Homo navigo) is a very particular form of Imperially-sanctioned human mutant, who possess the Navigator Gene and have existed within the human gene pool since the time of the Dark Age of Technology. All Navigators possess a third eye, commonly called the Warp Eye, on their foreheads which gives them the unique ability to see into the Empyrean without losing their sanity. Using the "psychic light" known as the Astronomican as a stable reference point, Navigators use the power granted by their third eye to guide human starships through the currents of the Warp. Their ability to sense the tides of the Warp is considered psychic, although Navigators never possess any psychic abilities beyond the powers of astronavigation their Warp Eye affords them. Since the Navigator Gene is hereditary rather than a recurring random mutation, the existence of Navigators is tolerated by an edict from the Emperor Himself issued at the time of the Unification Wars in the 30th Millennium as the Navigators and their politically powerful Navis Nobilite artistocratic houses were essential to the continued functioning of the Imperium's commerce and defence. Navigators all live within the special precinct of the Terran world-city that was given to them by the Emperor millennia ago. The politics of the Navigator Houses are known to be byzantine and treacherous in the extreme.

Afriel Strain
Afriel Strain soldiers are genetically-engineered warriors created during an experimental project conducted by the Adeptus Mechanicus, of which little is known about. It was an attempt to capitalize on the characteristics of the heroes of the Imperium's past's genetic material, to recreate all the best traits which had made them great. The project was an attempt to create the perfect soldier, which failed miserably. Afriel Strain warriors, for some reason, have the worst luck ever seen among humans, to the point that some Mechanicus adepts believe that their cloned genetic makeup may interface with the Warp in some way to alter the laws of probability. Afriels are normally albinos, with pale alabaster skin, pale hair and colorless eyes.

Beastmen
Beastmen (Homo sapiens variatus) are horned, hoofed, and quite hairy Abhumans. They were formerly recruited for the Imperial Guard, where they used their bloodlust to fight for the Emperor and atone for the sin of being born as mutants. They were led by other Beastmen called Packmasters. In the current edition of the game, "Pureblood" Beastmen are no longer seen in Imperial service, since overt mutants now only serve in the Forces of Chaos. No doubt Puritan elements of the Inquisition convinced the Administratum that the Beastmen could not be so radically altered from the normal human form without being tainted by Chaos. Some lesser variants of the H.s.variatus strain, who are less physically mutated than their peers, are allowed to still exist within the Imperial armed forces, where they are still used for cannon fodder and as expendable assault troops. These Beastmen are the Warhammer 40,000 equivalent of the Warhammer Fantasy universe's Beastmen.

Ogryns
The dim-witted human subspecies called Ogryns (Homo sapiens gigantus) evolved on high-gravity, low-temperature prison planets. They are huge and stupid, but unquestionably loyal once introduced to the Imperial Cult. Ogryns are used as the Imperial Guard's shock troops, and for this role, they are commonly outfitted with the Ripper Gun. The Ripper Gun is a weapon simple enough for them to operate, although some feral Ogryn cannot even fathom this device. Ogryn are also frequently used as bodyguards by Imperial Commanders. Ogryns tend to be claustrophobic and thus are difficult to transport. They are typically led by "Bone 'eads," who have undergone a procedure known as Biochemical Ogryn Neural Enhancement (or BONE treatment), improving their intellect to near-human standards. Sometimes, when speed is of the essence, Imperial commanders with a fresh batch of conscripted Ogryns don't bother to teach them the comparatively complicated use of the standard Ogryn Ripper Gun, merely giving them another club and telling them to smash up the enemy. As one might guess, the Ogryns are the Warhammer 40,000 equivalent of the Warhammer Fantasy Ogre.

Ratlings
Ratlings (Homo sapiens minimus) are small, loud, hungry and lecherous Abhumans who often serve as snipers in the Imperial Guard, a role at which they excel. Ratlings also serve as cooks for Imperial Guard Regiments, a skill they no doubt learned in order to feed their own seemingly bottomless stomachs; and they also have kleptomaniac tendencies, as Commissars report petty theft and illegal gambling rings increase substantially when Ratlings are attached to a platoon, company or regiment. One named Ratling world is Ornsworld, which was attacked by Abaddon the Despoiler during the Gothic War. Ratlings are a mutant sub-branch of the human race, like the Ogryn, who adapted to living in underground tunnel systems on worlds with hostile surface environments. Due to their size, they often bear the brunt of human soldiers' jokes, although more than one soldier has been saved by the Ratlings' superior marksmanship. Essentially, Ratlings are the Warhammer 40,000 equivalent of Warhammer Fantasy's halflings.

Squats
The Abhumans called Squats (Homo sapiens rotundus) originated on high-gravity mining worlds close to the galactic core, making them short, muscular and tough. Their homeworlds briefly seceded from the Imperium during the Age of Apostasy, though they later returned to the Imperial fold as autonomous but loyal worlds. Squats are talented engineers, and known to hold long-standing grudges, particularly against the Orks. In combat, Squats use combat motorcycles and support from superheavy artillery weapons, such as Leviathans and Colossi. Squats are probably rarely seen in gameplay, and are no longer officially part of the Warhammer 40,000 universe due to decisions made by Games Workshop; in the universe's mythology they are said to have been nearly driven extinct by the Tyranids in the late 41st Millennium. The Squat race was an equivalent of the Warhammer Fantasy dwarf, but since the removal of the Squats from the game, the part of a dwarf analogue in the Warhammer 40,000 universe was taken by the Tau-allied alien species called the Demiurg.

Gland War veterans
Gland War Veterans were created to fight invading Tyranids on the Forge World Dantis III, which was heavily polluted. The Mechanicus Tech-priests genetically modified several companies of the Lostok 23rd Imperial Guard Regiment to fight in the hellish conditions. They had many organs and drug-secreting glands implanted in their bodies so that they could survive in the Dantisian environment unprotected. Their combat abilities and physical aggressiveness were also genetically increased. Thanks to the heavy losses they took to ensure the successful defense of Dantis III, only three Gland Warriors are believed to have survived, who were taken by the Inquisition for study and debriefing.

Nightsiders
Nightsiders are Abhumans who live out their lives in near or complete darkness on worlds that either are so far from their primary star that little or no light is shed or planets that do not rotate and so one side is always facing away from the sun. Nightsiders may have developed larger eyes than a normal human, almost bulbous; others may have vestigial eyes with their other senses greatly enhanced to compensate for the near-blindness.