FORERUNNERS

Forerunners are most likely, the first lifeforms to appear in the universe after the Big Bang.  They only possessed a low-level intelligence level, enough for them to seek out food and consume it. Their food was any form of matter in the universe. Although they were unable to consume stars, they used starlight to guide them and flew to the stars like moths to a flame

The first forerunner appeared billions of years ago, in a dwarf galaxy far from the Milky Way. It was a lifeform made of powerful magnetic fields that developed around a gas giant. Once it attained sentience, it realized that eventually its homeworld would die and it needed to be able to leave it to survive. It created much smaller artificial lifeforms, consisting of the same form of EM field as his. To animate and program its "children", it created the first ever DNA molecules in existence. They were programmed to journey the universe and seek out other gas giants with similar conditions to their homeworld. Once found, the gas giant's magnetic fields were to be reshaped to allow their parent to "settle" there. Other of their functions included self-defense and self-replication with the use of any form of matter. When some Forerunners were destroyed due to various causes, their DNA would sometimes find favorable conditions on a planet's surface and form the beginning of organic life.

In essence, the original magnetic being can be called "God", as it was the cause of all organic life in the universe even though it was merely a side effect of its survival instinct.

Eventually, a swarm of Forerunners reached our galaxy and found a system in the Orion nebula, where a suitable gas giant was located and settled. 3 million years ago, the system's star went nova and nearly killed the gas giant lifeform. Seriously wounded, the lifeform lost all control of its Forerunners, whose programming was also damaged by the stellar explosion. They departed the nebula and began to travel the galaxy. Lacking their original purpose, their primary function became to feed on all matter around them and replicate more of themselves.

This large swarm was detected approaching an inhabited region of space in our galaxy. The swarm consumed all planets, asteroids, and even space dust in their path. This region of space, later named by humans the Sleeve of Emptiness, lay directly in the path of the Forerunners. Realizing that the swarm would destroy their races, the inhabitants of the region began to prepare for it. The two-headed Logrians chose to take their massive space habitats and attempt to outrun the Forerunners, fleeing from them. The Insects decided to hide themselves and wait out the "storm" by building a massive Dyson Sphere around their home star - thus making their star invisible to the swarm. Unfortunately, the sphere was not yet completed, when the Forerunners attacked and nearly destroyed it. Desperate, the Insects abandoned their worlds and left after the Logrians. Only the Delphons, who by that time visited many worlds in the galaxy, including Earth, decided to stay and fight, if not for their own survival, then for the survival of the races to come. After years of trying and failing to halt the swarm's advance, the Delphons came up with a suicidal plan to stop the Forerunners once and for all: whenever the swarm would approach one of their systems, they would detonate the systems star, destroying at least a part of the swarm. In the end, the Delphon civilization completely annihilated itself; however, their sacrifice was not in vain - the rogue Forerunners were destroyed as well.

Millions of years later, an archaeological expedition by the Confederacy of Suns to one of these annihilated systems discovered several Forerunners in an inert state. By feeding them matter, the humans managed to reawaken the ancient creatures, not knowing the danger they represent. The Forerunners managed to break containment and attacked and nearly destroyed a Confederate fleet in the system, constantly multiplying. Only a counterattack by their natural enemies, the entriphages, allowed the humans to stop another catastrophe.

After the fall of the Confederacy, several different parties found the Orion nebula and found not only thousands of Forerunners in the local gas giant and their guiding intelligence, but also humans descended from the colonists of Earth's first interstellar colony ship, the Alpha, lost for over a thousand years. These humans appear to worship the gas giant being as God, which also allows them to be reincarnated once they reach old age (i.e. none of the colonists have died of natural causes since the founding of the colony). They also appear to be able to exert some control over the Forerunners through the use of implants.

Unfortunately, the gas giant is slowly being depleted by ancient human-built biomechanical terraforming machines, who are mining a rare metal known as "metallic hydrogen" to fulfill their original programming and increase their numbers. This makes these so-called "phages" similar to the Forerunners. While the Forerunners are constantly trying to defend their creator from the phages, the machines' unique energy-absorbing armor and powerful lasers allow them to easily defeat the Forerunners and continue mining the gas giant.

Source: The History of the Galaxy series of novels by Russian science fiction writer Andrey Livadny. (and the related Wikipedia entry)

MAKLUANS / KAKARANTHARAIANS

Planet of Origin:  Kakaranathara (Aka Maklu IV), the fourth planet orbiting the star Maklu in the Milky Way galaxy.

Makluans are a reptilians species which has developed a highly advanced and peaceful democratic interstellar space faring society. 

A Makluan spaceship crashlanded in ancient China. Makluans are said to have been seen on Earth at the time as far as Camelot around the same time, and possibly other places as well. Makluans's  shapeshifting abilities made them able to walk among men without being recognised.

Makluans can function both as biped and quadruped; with green skin that average 32' in height when upright, reptilian scales, dragon-like wings, an elongated neck with rows of spikes running down the spine & tail, antennae, fan-like earlobes & clawed hands & feet. Their metabolism grants them rapid healing & the ability to regenerate certain of their body parts, entering a hibernationary state to accomplish this. Makluans are able to survive in the vacuum of space or under water for extended periods. Their lifespan is counted in centuries.Their wings endow them with flight capabilities under the speed of sound. They exhibit limited telepathy and  have natural shape-shifting abilities which allow them to assume a multitude of forms, able to alter not only their physical appearence but also their size, weight & mass by many orders of magnitude. If these polymorphic abiliites are inherent ot the species or has been artificially acquired s is unknown but it has been observed that individuals are able to transfer their life essence into the body of another living entity in case of death or serious injury; having done so, they are often able to transform the possessed body into their true form via their shape-shifting abilities. They can also exhale a corrosive chemical mist from their mouth, resembling fire, with varying degrees of intensity & accuracy.

Known individuals:  Fin Fang Foom, Axonn-Karr (who gave power rings to the Mandarin)

Source: Created by Stan Lee and Jack Kirby in  Strange Tales (vol.1) #89 (1961) and further developed in  Tales of Suspense #62 (Feb 1965) with the help of Don Heck. See also  New Excalibur #12

CHARRIDS

Charrids are humanoid agressive species with short snouts, sharp fangs and leathery skin. They are aggressive if not intelligent fighters, are known to eat their victims and have an extreme tolerance for pain. They are used by the Scarrans mostly as grunt soldiers and guards.

Source: Farscape universe

SCARRANS

Planet of Origin: Scaran Homeworld, in the Milky Way galaxy

Scarrans have developed a technolgically advanced agressive and expansive space-faring civilisation that goes back more than 12 000 years. Bipedal sexuate reptilian species with a humanoid body structure and skin ranging from pale white to dark gray in skin colour. They thrives in heat. In cold temperatures, their body heat drops rapidly. The species is split into two classes - the ruling caste and the soldier class.The head for the ruling caste and upper class appears to be flatter in shape, with well formed humanoid mouth, eyes, nose and chin while the head on the lower class is more horse-like in shape, with a protruding mouth, less developed eyes and slits instead of nostrils, with little or no nose potrusion. They are capable of huge amounts of brute strength. Their thick skin makes them impervious to small arms, though explosives in bodily orifices has proven fatal. This, coupled with  the razor-sharp claws on the Scarrans' hands, makes them formidable in combat.Still, Their main weapon is their natural heat projection. In this, Scarrans are able to blast large amounts of heat from their hands, redirected from their bodies.

Their main weakness is their dependency to strelitzia flower or the "bird of paradise flower" (as can be found on Earth) which they must keep consuming in order to maintain their high intelligence and remain intellectually competitive with other sentient races such as humans. They will only expand on planets capable of growing the crystherium plant. It is believed that it is this plant that mutates a Scarran's features, creating the distinction between upper and lower caste Scarrans. Naturally, the upper caste Scarrans would consume more of the plant, as it is also one of the race's delicacies.

The Scarran race is intensely interested in genetics, trying to splice DNA from other species into their own.

They have also mastered the art of creating replicas of people, known as bioroids. While being programmed, These replicas can carry only the memories of the original subject.

The scarans were onceat war with the sebaceans but the eidelons managed to put an eand to it. This truce held as long as the Eidelons were there but fell apart after their disappearance. Lack of knowldege of the adversary prevented an all out war but left the two warring factions in a stateo f cold war.

The Scarrans control at least two other species. The Charrids, used as grunt soldiers, and the Kalish (a sebascean sub-species)  as technicians. While the Charrids do not seem to mind being under the thumb of the Scarrans, the Kalish dislike it. As of the beginning of the 3rd millenium,  Kalish resistance has been formed, though its objectives and how they will obtain them are unclear.

The Scarrans have an imperial system and a body of government known as The Hierarchy, to which even the Emperor has to answer to and be judged by. 

Source: Farscape universe

ANCIENTS

The Ancients are a very technologically advanced insectoid species from another universe which developed a hive based civilisation and wormhole-based technology. Thin and bipedal  and brown skinned, they have four arms, two shorter upper arms, and two longer arms that are lower on their torso. The upper arms end in lobster-like claws while the lower arms appear to have three-fingered hands. They also have several shorter tentacle-like appendages both around and on their facial area. Shapeshifters, they can alter their appearance to look like members of the species they interact with.

Using wormholes as bridges to our universe, they modified several members of their own species, so that they  could live among species of our universe with the task to catalogue, report, and influence their activities.

When their planet became unable to sustin them, they started to look for a new world to establish themselves in our universe. They abducted a human to see if hey could cohabit with humanity on Earth but their experiment ended up with negative results. They soon after found a suitable planet.

Source: Farscape Universe

EIDELONS / SEBACEANS

Planet of Origin: Arnessk, in the Milky Way galaxy, which they inahbited 12 000 years ago until the planet became inhabitable due an alien attack..

The Eidelons is an advanced pacifist humanoid species which possesses a gland in their head that  acts as an empathic receptor, allowing the Eidelon to sense the wants and desires of those nearby, and vibrates to create an energy field which helps them develop tranquility and rationality. Using these powers, the ancient Eidelons could devise compromises that met the goals of the involved conflicting parties and could ensure that a peaceful solution to conflicts would be accepted. Eidelons look remarkably like humans but have an internal very different cranial structure, being able to open up the upper part of their head when their gland is in action.

Looking for a species to serve both as bodyguards and as enforcers of peace. They abducted primitve humans on planet Earth some  27,000 years ago and genetically enhanced them. This new species became known as the Sebaceans and they became the Eidelons' trusted acolytes. They took on the name of Peacekeepers due to their function.

After Arnessk became uninhabitable and the Eidelons has vanished (either fleeing to other planets or entering suspended animation outside of time. The Peacekeepers attempted to carry and kept the peace with military force, and eventually became the militaristic Peacekeeper empire.Today, only a handful of Eidelons remain.

SOurce: Farscape Universe.

STARRO / STAR CONQUEROR

Sentient starfish-shaped alien species with a central eye and prehensile extremities. They are also known as Star Conquerors. Adult Starro can asexually generate parasitic clones from their own body and command them to act in accordance with his will. Although equipped with only limited mobility, Starro parasites can attach themselves to a victim's face, whereupon they attack a body's central nervous system, subsequently taking control of both their mind and body, acting as transmitters of the adult starro's will. A Starro parasite can maintain control over its victim for an extended period of time, forcing them to obey their every whim, even if it goes against the nature of the selected target. This ability only works so long as the parasite maintains physical contact with its victim. Once the parasite is removed, the victim regains control of their mind and motor function.

Starro can absorb energy and rechannel it as powerful blasts of energy, which it directs through the tip of each tentacle and generate energy fielsd allowing them flight in both outer space and atmospheric environments.A fully grown Starro is impervious to most conventional forms of attack. Gunfire and similar weapons are ineffective against a Starro. Starro can also change the color of its skin for different purposes,

The first passage of a Starro on Earth happened in 1960. It was destroyed shortly after its arrival but surviving fragments managed to redevelop sentiance afterward from time to time.

Source: DC Universe. The character first appeared in Brave and the Bold #28 (Feb. - March 1960), Starro the Conqueror was created by writer Gardner Fox and artist Mike Sekowsky. The Starro species was further developed by writer Grant Morrison.

THASIANS

Planet of Origin: Thasus, a dry planet within 1000 light years from Earth

Thasians are non-corporeal entities with powerful psychokynetic powers which they can transmit to others (as it was the cae in the 23th century when they rescued a young human boy whose parents spaceship crashlanded on their planet.

Source: Star Trek universe (TOS: "Charlie X")

FIRST FEDERATION

Planet of Origin: A planet orbiting Fesarius, a K Orange star less than a thousand light years from Earth.

The First Federation members are one meter tall bald humanoids who developed a peaceful yet recluse and non-expansive highly advanced spacefaring civilisation. Their territorial space is surrounded by a network of space buoys and contact with other species are usually dealt with kilometers wide spherical one-man ships, leading to believe that space travel remains rare among the species. 

First contact with humanity was made in 2226.

Source: Star Trek universe (TOS: "The Corbomite Maneuver")

GALAXIANS /GALAXIENS

Planet of Origin: Original planet unknown. After it underwent a critical greenhouse effect some 2000 years ago. Three quarter of the population left in space arks and relocated on the First of the two moons of planet Aktarka, orbiting a G star in the Milky Way. A minority of Galaxians stayed on their homeworld but all contact was lost with the exilees.

The Galaxians are a pacific, even  friendly, species of one meter tall humanoids that have developed an advanced but ot expansive interstellar space-faring civilisation. Their skin was originally of a light orangeish color, but after their planet was exposed to heavier sun exposition, they slowly turned s to black over generations. Those who relocated to Aktarka's moon turned to green skin. All quite ressemble bald teddy bears. A minority, mainly among females, have been known to develop psychic powers.

Galaxian society is very democratic, one with a constant )sometimes even daily) exchange of social tasks even in the sharing of tasks. The annual head of state is called the Prince-of-the-Year and is the Galaxian who received the most merit points over the past year.

Over him is the Council of Elders which is made up of five Galaxian patriarchs which seems to be an half-honorific title for those chosen as they dont always seem to have much credit given to them.  The younger Galaxians are quite aware of their elders deficiencies and often take them half-serously. 

Source: The Scrameustache series, by Gos and Walt

OVIONS

Ovions are a four-armed bipedal man-sized insectoid species that were members of the Cylon Alliance to whow Their tylium mines were an extremely valuable asset.  They manage a Gambling ans entertainment complex on the surface of their homeworld to attract preys. Individual humans are trapped selectively and taken into the hive-like structures underground  to be placed into chambers which slowly transform them into food. Ovions occasionally prowl discreetly on the entertainment level, but generally remain out of sight. 

They are now presumably extinct since their world was destroyed in the explosion of their tylium mines.

Source: Battlestar Galactica Universe  (Saga of a Star World). 

AQUANS

Planet of Origin: Argo,  a seismically-unstable planet. Once a land planet, but its surface became almost completely covered by water, following a series of violent seismic disturbances, leaving only a single large landmass, with a few associated outcroppings.

The Aquan are an humanoid species which developed an advanced planetbound civilisation. They are good example of forced evolution as originally air-breathers were they mutated themselves to become able to breath underwater after massive planet-wide earthquakes flooded the entire planet.

They are governed by the Ruling tribunal of the Anquans and follow the Aquan Ordainment, an ancient set of rules.

Source: Star Trek Universe,  (TAS: "The Ambergris Element") 

SHANSHEETH

The Shansheeth are species of avian bipeds. Two meters tall, they have hunched shoulders with a long neck protruding from the middle section of their body and a vulture like head. They have five digits clawed hands and feet. Apart of their head, neck, feet and hands, most of their body is covered in feathers. They are able to project energy beams from their hands and like wearing robes and jewels.

A peaceful advanced space faring civilisation led by a political enitiy known as the Wide Wing of the High Shansheeth Nest, they have been known amongst the interstellar community as galactic undertakers, journeying through space in tribal groups to return lost heroes to their kin. .They employ shards of black stones called epitaph sotnes which they use to project hologrphic images to communicate with other species and  have also been known to use devieces called memory weaves to extracting memories and turning them into physical objects.

 Source: Doctor Who Universe (SJA: Death of the Doctor) 

QETESH

The Qetesh is a species that developed an advanced civilisation capable of star travel. They feed off powerfukl emotions such as excitement in people's lives, draining their life essence with it and are therefore masters of emotional manipulation ot achieve sustainance. They are also known as "soul-stealers".

Their stomachs existed outside their bodies, and they did not need air to breathe. The mobile part of their body has been known to look human, but they are most proabably albe to make it match the appearance of their prey's nature to better manipulate them into generating emotionnal food.

Source: Doctor Who Universe (SJA: Goodbye, Sarah Jane Smith)

FLESHKIND

Planet of Origin: Fleshking planet, part of a binary planetary system (the other planet being the Metalkind planet) in the eye of the Tornado Nebula.

The Fleshkind is a carbon-based humanoid species that developed an advanced civilisation and possesses interstellar-range teleportation technology as well as advanced genetic engineering. 

They are externally almost undistinguishable from humans but can shoot energetic discharges from their hands to place others in a trance. Given the fact that they have been known to develop living weapons of high destructive power, this ability might have been engineered.

The Fleshlkind was at war with a Metalkind race that lived on the twin planet of their homeworld after they started mining operations to mine precious ore on  the Metalkind planet; ore which was in fact the the Metalkind's children. Discovering this fact, the Fleshkind started using the so-captured Metalkind as slaves, which lead to the war.

Th war had come to a stalemate as of the beginning of the 21st century when the Flehskind developed a living weapon capable to destroying all the Metalkind but the weapon was lost, possibly restoring the stalemate.

Source: Doctor Who Universe (SJA: Sky)

METALKIND

Planet of Origin: Metalking planet, part of a binary planetary system (the other planet being the Fleshkind planet) in the eye of the Tornado Nebula.

The Metalkind is a species of sentient  humanoid bio-metalloid  boron-based lifeforms. The Metalkind was at war with a Fleshkind race that lived on the twin planet of their homeworld after they started mining operations to mine precious ore on  the Metalkind planet; ore which was in fact the the Metalkind's children - which were then used as slaves by the Flehskind, leading to the war.

This leads to believe that the Fleshkind was originally more technologically advanced than the Metalkind, being the first one to venture on the other's planet and starting its exploitation. As of the 21st century, after hubndreds of years of war, both species possessed weapons that enabled some kind of stalemate bwetween them, as well as interstellar-range teleportation technology - which might have been the initial way the Fleshkind made it to the Matlakind planet.

To end the stalemate, the Fleshkind had developed a  living weapon that could destroy the Metalkind but the weapon was lost, possibly restoring the stalemate.

Source: Doctor Who Universe, (SJA: Sky)

VENDORIANS

Planet of Origin: Vendor (Vendoria)

An advanced cephalopodic sentient, tentacled shape-shifting species.  In their natural form, Vendorians look rather like floating orange lamps adorned with six trailing tentacles. They had great agility and grace, and reflexes superior to those of a human.

Because of their ability to rearrange their cellular structures at will, thus taking on the shapes of various humanoid species,they are looked upon them with suspicion by other species. While Vendorians may assume many shapes and identities, the longer they remain in one form the more characteristics of that form they assume as  they can absorb memories and personality traits of an individual through touch. These memories and traits become more ingrained the longer or more frequently the Vendorian assumes the form; if maintained long enough, the absorbed traits eventually become part of the Vendorian's own personality. 

In the 23rd century, due to their practice of deciet as a way of life , they have been judged psychologically unfit for the interstellar communicty. Their planet has been quarantined to avoid them inflitrating other worlds and spreading chaos.

Source: Star Trek Universe ("The Survivor")

URSINOIDS

The Ursinoids are a sentient bear-like humanoids species which had devleoped spare faring as of the 23rd century. They have large fangs and were completely covered in fur. 

Note: They are reminsicent of the Bulrathi of  Masters of Orion

Source: Star Trek Universe ((TAS: "Mudd's Passion"))

TRAVIST POLONGS / POLONGANS

Planet of Origin: Polongus

Travist Polong are a species of small, sentient slug-like, multi-eyed beings. Some are known to have come to Earth at some point in the early 2010ies.

Source: Doctor Who Universe . (SJA: The Wedding of Sarah Jane Smith)  (SJA: The Mark of the Berserker)

GORGON

Planet of Origin: Gorgos ((100,000,000 light years from Earth)

The Gorgons were a species of intelligent parasitic beings which possessed their hosts. Non corporeal, individuals look like a group of blue ethereal serpentine forms hovering in the air. They had some psychic powers, specifically mind control and the ability to petrify creatures within a matter of hours. In order to do so, it needs to leave its host and make contact with the target. They can be reflected by a mirror, causing them to return to the host and turning it to stone. While in the host, they greatly increased its lifespan, letting one human host live for over 200 years. This was much less than the Gorgon's natural lifespan of thousands of years, which meant they had to frequently switch hosts.

Three Gorgons came to Earth around 1000 BC via a talisman, entering into Greek mythology along the way. One Gorgon was slain by a Greek hero, another by a professor and his wife in 1959, and one survived up til 2010. This Gorgon eventually inhabited the body of an abbess and led the sisterhood of nuns at St. Agnes Abbey, manipulating their minds to serve it for over 200 years. The Gorgon led the nuns on a mission to retrieve the talisman so as to call the Gorgons from their home world to invade Earth and take all of humanity for their hosts.

Source: Doctor Who Universe (SJA: Eye of the Gorgon)

EKNODINE

The Eknodine are a symbiotic sentient alien species that can live inside of specimens of other species, extending their lifespan. As a defense mechanicsm, they can extend a green eyestalk from their hosts' mouth, which can spray a green cloud which turn a human-size hostile into dust.
Note: There are similarities between this species and the Goa_Uld. and the Hive/Ganglion.
Source: Doctor Who Universe (DW: Amy's Choice)

TENZA

The Tenza is a species whose young were raised by other species. To that end, they possessed advanced, though subconscious, psychic powers, allowing them to live among the alien culture in which they were being raised. They born in space, where they drift until they found a habitable world. There, they find a family to live with, then infiltrate it. The Tenza infant would adapt itself to suit its environment and alter the memories of its surrogate parents and those around them. After that, the Tenza would live out its life as a member of the surrogate parents' species without conscious realization of its true nature.  If the Tenza felt threatened, its telepathic abilities played havoc with its environment to keep it safe.  They used a perception filter to remove inconsistencies in their histories. Their telepathic abilities are known to be able to scan space over distances of millions of light years.

Source: Doctor Who Universe (DW: Night Terrors)

BAJORANS / PROPHETS / PAH WRAITHS

Planet of Origin: Bajor, the 7th planet orbiting the star Bajor-B'hava'el, an earth type planet with five moons. A Day on Bajor has 26 hours. Bajor's atmosphere has a greenish tint; as a result, oceans viewed from space will appear more green than blue.

The Bajorans are a pacific  humanoid species who developed advanced civilisation about 500 000 years ago and started space faring in the 16th century. They were invaded in 2328 by the Cardassian Union, with who they had aligned themselves some time before. They were occupied for 40 years, during which time many Bajorans were forced into slave labor. Many fled and hid in refugee camps while other got involved in the terrorist resistance movement. In 2369, the Cardassian civilian authorities ordered the military to withdraw from Bajor, after which the Bajoran provisional government invited the United Federation of Planets to set up base in the system and requested membership into the Federation. Soon after, a stable wormhole was discovered in the system, making it a strategic position on the galacitc scale and a key entry point for the Dominion, an invasive civilisation lying at the other end of the Wormhole. Bajor finally formally joined the Federation in 2376, the year after the Dominion War ended.

The Bajoran people were originally divided into castes, called d'jaras. When the Occupation began, the d'jara system was abolished.

The Bajoran religion, known as the Way of the Prophets, is the major unifying force on the planet. Its religious figures are entities refered to as The Prophets, or "Wormhole Aliens" which, also they claim to be of Bajor, exist within the system's wormhole, referred to as the Celestial Temple by the Bajoran people. Their motives remain unclear; on several occasions they proclaim their disinterest in the physical world, while at other times actively participate in the physical world, most often in the general interest of Bajor and its people. People who followed the will of the Prophets are said to be permitted to enter the Celestial Temple and dwell with the Prophets upon their death. The Prophets are also believed to have given Bajor its main religious artifcacts, were discovered 10 000 years ago, the "Tears of the Prophets", crystalline, hour-glass shaped orbs , glowing and  floating within their containers and have powers defying scientific explanations, the most common being to stimulate visions that are beleived to communications from the Prophets. Some prophets, known as Pah Wraiths, are said to have been imprisoned by their kin on Bajor in a physical prsion known as the Caves of Fire for having tried to seiz control of the Celestial Temple in the past.

Source: Star Trek Universe

ASGARD

Planet of Origin: Unknown, in the galaxy of Ida
The Asgard are diminutive humanoid species which developed a benevolent highly advanced space-faring civilisation governed by a Hihg Council.  They were once part of an alliance of four great races with the Ancients, Nox, and Furlings and visited Earth during antiquity and protected a number of planets in the Milky Way, mianly from the Goa'uld with whom they signed The Protected Planets Treaty is an armistice between the Goa'uld and the Asgard, first referred to specifically in "Fair Game" when Earth is included. The treaty covers 27 planets including Earth,^[6] and ensures that those planets remain free from Goa'uld domination. Other planets in the treaty include Cimmeria,^[1] K'Tau,^[11] PX3-595,^[13] the second planet of the Adara system,^[3] and Galar.^[14] . As of the 20th century, the Asgard are a dying race. Having lost the capacity for sexual reproduction, they perpetuate themselves by transferring their minds into successive cloned bodies, leading to an irreversible degeneration of their genome. They chose to commit mass suicide in the beginning of the 21st century, having arrived at the end of their degenerative cycle, by exploding thri homeworld to prevent that their knowledge fell into the wrong hands.
A renegade faction of Asgard splintered from the others 10,000 years ago over their belief that they should experiment on humans to solve their cloning problems. They traveled to the Pegasus galaxy and continued their experiments, but were forced into hiding after the Wraith defeated the Ancients. 
Amongst the most significant technological advancements of the Asgard are beaming technology, intergalactic hyperdrives, advanced shiled technology and plasma beam weapons. They are very advanced in cloning techniques and have the technology to upload and store consciousnesses and transfer them to new bodies. Neutronium is a key element of Asgard technology. Source: Stargate Universe

AMNION

Amnion is an adavnced space-faring vaguely humanoid species which looks like " "a humanoid sea-anemone with too many arms." They differ greatly in appearance from one another, with differing numbers of limbs, eyes, and other organs, as well as  in size and shape. While being physically very different, they share a hive mind with the major instinctive drive of the expansion and propagation of the Amnion species, leading them to assmiliate other species by turning them into members of their own.

They possess  mutagenic technology that gives them the ability to rewrite the DNA of a non-Amnioni to turn him into an at least partially Amnion. Basic life processes remain intact, but protein and DNA structure are radically different. The new mutants can breed with each other (though not with mutated members of other species) and display a significantly increased level of intelligence.

First contact was made betwwen them and humanity while humanity was already travelling interstellar journeys.
Source: Stephen R. Donaldson's The Gap Cycle

GREATEST AMERICAN HERO ALIENS

Planet of Origin: Unknown, formerly a garden planet, now a wasteland. Its name is unpronouncable by humans.

The alien seen in The Greatest American Hero is from a green skinned humanoid species that developed an advanced technological civilisation. They had use of spacecrafts, teleportation and suits enabling their wearer to use flight, super strength, resistance to injury (including direct bullet hits to areas covered by the suit), invisibility, precognition, telekinesis, x-ray vision, super speed, pyrokinesis, holographic vision, shrinking, psychometry, and sensitivity to the supernatural.

According to the alien, his planet (which now looks remarkably like Mars) used to be a garden planet but is now a wasteland. He is therefore, as of 1983, among its rare survivors. He came to Earth to give a human one of their suits with which he hopes humanity will be saved.

Possibly coming from the same planet as him is a small creature floating in the air which ressembles a small snake with a torso, two arms a vaguely humanoid head on which is a long articulated antenna.
Source: The Greatest American Hero Tv show, ABC, 1981-1983

GAMILAS

Gamilas are a hibe-minded bipedal species which developed an advanced space faring civilisation.Knowning their planet doomed, they tried to invade Earth around 2199 and eradicate humankind. This decision caused a split of the hive personnality, one portion of it being against destroying another species. It sent technological information to Earth that would allow the humans to defend themselves. The Gamilas were eradicated.

Source: Space Battleship Yamato live action.

SLENDERS

Slenders are a species of tall circa 4 meters tall grey humanoids who developed an advanced space faring civilisation. They are an intrusive species, harnessing other species such as  skitters  and humans to control them and armed Mech drones to ensure their security. Graceful and slender, they can move very quickly in an Earht type gravity and appear to have features ressembling cetacean mammals. They are the apparent power behind the invasion of Earth. 

Source: Falling Skies

IXTL

Planet of Origin: Unknown but presumably destroyed for a long time.
Ixtls are a very ancient sentient species, thought to be extinct, although some specimen could still be floating in the emptiness of space in a state of suspended animation. They are red colored, with four legs and four arms ending in eight fingers. Their cylindrical body is virtually immortal and they have in full control of its  molecular structure, enabling them to survive unprotected in space for eaons in suspended animation and allowing them to withstand very high energetic discharges. To reproduce, Ixtl need what they call a Guul, i.e.living hosts in which it deposits their eggs. The eggs need only a few hours to hatch and then feed their living host.
Source: A.E. Van Vogh, The voyage of the Space Beagle

ASGARDIANS

Planet of Origin: Unknown but their current place of residence is Asgard, a place situated in a wormhole network (of which Earth is part) englobing 9 worlds. Asgardians have developed the Bifrost technology enabling them to teleport themselves instantaneously to any of the 9 worlds using the subspace network of the wormhole.

Asgardians are a highly advanced humanoid species. Earth'sNorsemen and Germanic tribes used to worship the Asgardians nearly a millennium ago. Even though certain Gods are still interested in humanity such as Thor, the Asgardians do not have any more active worshippers or seek to have any. Asgardian flesh and bone is about three times denser than similar human tissue, contributing to the Asgardians superhuman strength and weight. An average male god can lift up to 30 tons while an average female can lift up to 25 tons, but there are those that exceed these specifications. They  are also gifted with extremely long life, but are not immortal. They are also immune to all terrestrial diseases and are highly resistant to conventional forms of injury. The metabolism of the Asgardians gives them superhuman endurance in all physical activities. Their close genetic and morphologic resemblance with humans leads to believe that those two species, along with the other ones of the the 9 realms could be of a same origin.

Asgardians residing on theworld of Vanaheim are refered to as Vanir while the ones residing in Asgard itself are refered to as Aesir.

The other species of the 9 realms are:

• The Dwarves: Dwarves are small and stocky with an average height of 4 feet. Dwarves live in Nidavellir and maintain peaceful relations with the Gods. They tend to be either craftsmen or farmers and have created weapons for use by the Gods such as Mjolnir and the spear, Gungnir.
  
  
• The Elves: The two types of elves that inhabit the land are the Light Elves and the Dark Elves. The Light Elves live in Alfheim while the Dark Elves live underground in Svartalfheim. Both species are similar in the respect that their body types can differ greatly in size anywhere from 4 feet to 8 feet, and have proportionally long limbs. Light Elves have lighter skin tones while Dark Elves are darker.
  
  
• The Demons lives in the realm of Muspelheim. Demons are similar in size to the Gods, but are engulfed in fire. They tend to be nomads but will travel into other dimensions for the purpose of war. All Demons are the offspring of the fire demon who is said to be older than asgaridn culture, Surtur.
  
  
• The Giants: the Giants live on Jotunheim. They are also humanoid, but are more Neanderthal-like in body structure. They are the traditional enemies of the asgardians with whom they fought a millenia-long war that ended in 965 after they tried to settle on Earth. They were repelled to their homeworld, which was devastated and left without means to travel using the Bifrost network. Most stand up to 20 feet tall, but some can reach 30 feet. Giants usually lead a hunter/gatherer type of life, but will war with the asgardians on occasion because they are jealous of their superior abilities. The first of the Giants was the Ice Giant, Ymir, who existed before any of the Asgardians. Many different races of Giants arose in Jotunheim, including the Ice, Mountain, Rime, Storm, and Frost Giants. The Frost Giants are the direct descendants of Ymir. The Giant Laufey was another monarch who lost the war  against the Asgardians; In tribute to Laufey's courage and to try to seal a peace treaty with tthe giants, the asgardian king Odin adopted the giant's infant son Loki. Two other giants of note were Fafnir II and Fasolt (both deceased), who built Odin's palace in Valhalla in exchange for a Goddess, and battled over a magic ring and treasure that was given for the Goddess being released. Giants have also been known to reproduce half-breeds that look like asgardians.
  
  
• The Trolls: Trolls are massive creatures covered in hair with an orange skin tone. They average in at 7 feet, and they live in settlements scattered throughout the land. The trolls are incredibly strong, surpassing the strength of the asgardians, and puts them on similar ground with the Giants.Thor. Trolls usually work as miners and metal workers.

Sources: Thor movie, Marvel Universe, More on Marvel.com: http://marvel.com/universe/Asgardians#ixzz1S2qPajjt

SKITTERS

Skitters, are an aggressive space faring species of six-legged reptilian clawed insectoid aliens with two prehensile arms. They are nocturnal, speak in a kind of strange language with a manbidle equipped mouth and possess light-green eyes with vertical black pupils. They appear to have armor that covers their body except for their head and legs. They invaded the Earth in the early 21st century and destroyed all major cities. At first they were not engaged because humanity thought they might be peaceful. They "harness" children using a centipede-like parasite to control the children's minds so they can communicate with humans. They use bipedal Mechs and airships. 

Source: Falling Skies series 

BATTLE LOS ANGELES ALIENS / BLAA

Planet of Origin: Unknown. Given the decrepit appearance of their ships and equipment, it's possible that the aliens that come to Earth in 2011 may not be part of the dominant force in their homeland and may be looking for a new home planet, possibly due to their old home being uninhabitable because of warfare or some other cataclysm. This would explain their War of the Worlds-esque landing method, as well as their relatively low level of technological advancement for a spacefaring civilization. It is theorized  that they are invading for Earth's liquid water.

Description: The Battle: Los Angeles Aliens (often refered to as Blaa) are an aggressive advanced spacefaring caste-based bipedal carbone-based organic species practicing heavy cybertransplant on themselves.They are divided in castes, easily recognisable by their morphological specificities and the nature of their implants. 

Four warrior castes are known to exist.The warriors are highly developed bipeds with four fingers hands among which are opposable thumbs. They sport redundant arteries and other blood vessels. Their heads are actually entirely sensory organs. Their brains are located in a cavity behind their hearts, directly attached to the spine. They have large numbers of stem cells and platelets, enabling them to regenerate whole limbs that may be lost in combat, while their hardened exoskeleton allows them to take heavy damage before being too injured to continue fighting. All warriors have substantial amounts of machinery implanted into their bodies, including communication, cooling, and weapons systems. Their perception is also very acute, supplementing their precognitive and retrocognitive abilities. 

Infantry Caste: The Infantry Caste can be identified by weapons grafted onto each arm where grasping hands would be. Their average height is about 8'1". While they are taller than humans, they are proportionately thinner. All of their vital organs are concentrated behind layers of muscle and arteries in the right of their chests. A cooling system is also integrated into their body, with a heat-dispersing fan located in front of their organs. Unlike many of the other castes, they do not have as much machinery located on their back.

Officer Caste: The Officer Caste is the easiest caste to differentiate from the rest, identifiable by their slender build and four mechanical legs replacing their biological ones, which enable them to move at speeds of up to 40kph/24.8mph with relative ease. They are also the tallest caste with an average height of 9'4". The Officers are specialized in commanding groups of infantry, augmented by an unusually large, well-developed brain and very keen eyesight which has been supplemented with additional electronics. The Officer caste have the most substantial amount of cybernetic enhancements. As their legs have been wholly replaced, they are able . Their right arm has an implanted weapons system that trades firepower for accuracy, while their left grasping hand has been replaced by a mechanical claw. 

Operations Caste: The Operations Caste share many similarities with the General Infantry Caste, with a few notable exceptions. The Operations average about 6'11". The special forces appear to be a more intelligent Infantry soldier, expected to undertake specialized goals beyond that of simple shock troops. They also appear to be a middling caste, lacking the firepower of the Infantry and the intelligence of the Officer. Unlike the officer and infantry castes, the Operations have retained their left grasping hand and are able to make use of hand signals. Their weapons systems sport greater accuracy than those of the general infantry, but a less-powerful grenade launcher.

Intelligence Caste: The Intelligence Caste is likely specialized in their namesake, gathering information and laying down lines of communication. Averaging about 5'10", the Intelligence caste are the shortest and stockiest of all known warrior castes. Unlike all other warrior castes, the Intelligence Caste lacks any integrated weapons systems. However, they retain the large amount of cooling and communications machinery grafted to their backs. The lack of weaponry is made up for by their ability to utilize both grasping hands, which they use to operate machinery and vehicles, such as driving ground artillery platforms and operating walking guns. 

Water Extractot

The full extent of their space-faring capabilities is not known. Most of their light weaponry uses projectiles, but they also use heavy energy weaponry. Although the known vehicles make use of different forms of propulsion, such as walkers and hovercrafts, none are wheeled. All are oriented toward greater mobility, at the cost of armor and therfore, the protection of the users. The have intensive use of cybernetic implants and replacement of actual body parts and do some genetic engineering to increase efficiency of castes,An extreme case of such engineering is the Water Extractor, a specialized alien, used as biological pump that is used to move massive amounts of water quickly, growing as large as 100 feet in height. The Extractor's organs have been greatly reduced and compacted, leaving only organs that are vital to life functions. Extractors are highly intelligent and use an advanced form of communication to coordinate their actions for maximum efficiency. The extractors are deployed along with the initial invasion force, landing off-shore and using modified tentacles to quickly pull water from the surrounding environment. 

The aliens  launched a surprise invasion on Earth, most likely motivated by a need for a new home or colony on the 12th of August, 2011. Originally mistaken by the Humans to be clusters of meteors, their  spacecraft landed off the coastal shorelines of twelve of the world's major population centers. Their ground forces subsequently attack many of Earth's major cities, including Paris, London, Moscow, New York, Hong Kong, Rio de Janeiro, and Tokyo. Their aircrafts eventually arrive and appear to easily take control of the air above the cities  from the human Air Force. Besides their ground and large air forces, they deployed a sort of command center controlling unmanned flying drones. In Los Angeles, within a few days, the drones  pushed most of the U.S. military force out of the city, killing thousands during the engagements but a squad of Marines  able to destroy the command center, disabling all of the drones and depriving them of their air assets. These Marines later retreat back to a command post, and join up with thousands of reinforcements ready to try and take back Los Angeles from the invaders. 

Souce: Battle Los Angeles, Battle Los Angeles wiki