StarCraft

Three playable classes, Protoss, Terrans and Zerg, each have a single campaign in each StarCraft real-time strategy game, although there are times when the player may have control of two species at once.

Protoss

The Protoss are a fictional race of humanoids in the StarCraft series. Comprised of two societies, the conservative Khalai Protoss and the exiled dark templar, the Protoss are depicted as a physically strong species with access to advanced psionic abilities. The Protoss are considered the most technologically advanced race of the series and are the focus of two episodes within StarCraft and its expansion Brood War, as well as featuring in campaigns in the authorised add-ons Insurrection and Retribution. Protoss strategy in-game is usually built around the quality of units the player controls rather than the quantity. Originating from Aiur, a planet on the fringe of the galaxy, the Protoss are normally shown in the games and the novels of the series as the nemesis of the Zerg.
Society
Protoss society is shown in the background of the series to have been tribal with a strong warrior culture, until a planet-wide civil war allowed a mystic, Khas, to access a natural psionic link shared by all Protoss. Khas' discovery and teachings, labelled the Khala, are then used as a base for a new caste-based society. The judicator caste forms the Conclave, the ruling body of the Khalai Protoss, the templar caste consists of the military and the khalai caste includes all other Protoss. The player controls a templar character in the Protoss campaigns of all the video games to date. Khalai Protoss society is depicted as being stubbornly conservative while maintaining the warrior culture and honour values of the tribal system.
The backstory presented in StarCraft's manual and in the novel Shadow Hunters also shows the rise of a second society of Protoss known as the dark templar, a sizeable minority of the Protoss who reject the Khala out of fear of losing their individuality inside the psychic link. The dark templar are treated as heretics by the Khalai Protoss and are forcibly evicted from Aiur. Despite their persecution, the majority of dark templar do not hold anything against their estranged brethren, seeking to defend Aiur secretly in any way they can. The dark templar are presented as nomadic, only settling on the planet Shakuras to study a Xel'Naga temple there. After the conclusion of StarCraft, the two groups begin reconciliation but are marred by mutual distrust of each other.
Depiction
The Protoss are humanoids, around three meters tall with two luminous eyes, typically gold or blue. With two fingers flanked by two opposable thumbs on each hand, two large toes on each foot, double jointed legs, broad chests and shoulders with narrow waists, Protoss are very agile and physically strong. A bony crest extends back from the crown of the head, with long neural strands sprouting from the back of the head. These strands facilitate the basic psychic communal link all Protoss naturally share. Each Protoss naturally has a different skin shade that corresponds to the tribe from which they are descended. The Protoss do not possess any visible ears, mouths or noses, but are able to communicate telepathically and possess strong nasal sensitivities. Protoss do not need to eat or drink, but are shown in The Dark Templar Saga to instead absorb energy from a form of photosynthesis. The average life expectancy for a Protoss is several hundred years. Little is known of the internal anatomy of the Protoss.
Appearances
The Protoss are introduced in the third campaign of StarCraft. In the events immediately preceding the beginning of the game, the Khalai Protoss have become aware of a Zerg invasion of Terran worlds, and responds by sending a fleet commanded by the high templar Tassadar to destroy infested Terran worlds. Tassadar instead disregards his orders to massacre the Terran populations, attempting to destroy the Zerg by conventional means. Tassadar later meets a dark templar, Zeratul, and embraces the dark templar culture, prompting the Khalai Protoss to brand Tassadar as a traitor. Zeratul accidentally gives the location of the Protoss homeworld Aiur to the Zerg, leading to a Zerg invasion that devastates the planet. At the end of StarCraft, Tassadar sacrifices himself to save his people by destroying the Zerg Overmind.
The Protoss return in Episode IV of Brood War, the expansion to StarCraft. Following immediately on from the conclusion of StarCraft, Zeratul and a ranking templar Artanis evacuate the surviving Khalai Protoss from Aiur to the dark templar colony world of Shakuras. After the Zerg follow them to Shakuras, Zeratul and Artanis harness the energy of a resident Xel'Naga temple, scouring the planet of all the Zerg. The Protoss attempt to rebuild their lives on Shakuras, but are interrupted by a Zerg raid commanded by Sarah Kerrigan that kidnaps the dark templar leader Raszagal. Using Raszagal as leverage, Kerrigan blackmails Zeratul into killing a new Overmind in incubation. Zeratul complies, but later kills Raszagal after it is revealed she has been brainwashed by the Zerg. Zeratul disappears while Artanis takes leadership and tries to reconstruct his people's civilization.

Terrans

The Terrans are a fictional future version of humanity in the StarCraft series. The Terrans are the most splintered of the StarCraft species, consisting of multiple factions that not only fight the other races but each other as well. Considered an adaptive and mobile species, the Terrans are noted in the lore of the series for their ability to quickly access and drain a planet's resources. The Terrans have been dedicated a campaign in each real-time strategy video game installment to date, and are defined in-game by their specialisation of units and tactics of defence and mobility. In the series' storyline, the Terrans are usually displayed as being caught in-between the conflict between the Protoss and Zerg while also dealing with frequent civil wars.
Society
The Terrans are shown to be the most fragmented of the races in StarCraft, with multiple factions all vying for dominance over each other. Numerous factions are used throughout the series, ranging from national governments and corporations to rebels and criminals, although only four factions exhibit any major influence on the overall story arc. The first faction referred to in the backstory of the series is the United Earth Directorate (UED). A unified government of almost all the nations of Earth and several colonies both within and outside the solar system, the UED operates under a policy of "enlightened socialism" but is noted for its harsh methods of public order and media censorship. It is also seen as an advocate for eugenics, resulting in the mass murder of millions and exile of other unwanted criminals and genetic mutants for colonization of the distant Koprulu sector of the galaxy in which the series takes place. The UED remains outside the events of the series until Brood War, where it takes interest in the discovery of the Protoss and Zerg, the first contact between humanity and aliens. The player controls the UED faction in Episode V of Brood War.
The exiled prisoners from Earth form the Confederacy of Man in the Koprulu sector. The Confederacy's inner workings are elaborated on in the novels Liberty's Crusade, Speed of Darkness and Nova. Taking the role of the primary antagonistic faction in StarCraft's Episode I, the Confederacy is shown as the most powerful faction in the sector at the beginning of StarCraft, but is depicted in the novels as being brutal towards the public and corrupt at the highest levels on its capital Tarsonis. The player gets to control a division of the Confederate Security Forces in the prequel shareware campaign for StarCraft. Due to the brutality of the regime, it is opposed by a variety of rebel groups and is eventually overthrown by the Sons of Korhal. The Sons of Korhal, a rebel group led by Arcturus Mengsk that the player controls during Episode I of StarCraft, form the Terran Dominion to replace the destroyed Confederacy, with the planet Korhal IV as the capital. The Dominion is an autocracy with Mengsk as its emperor. The Dominion's operations are built on in The Dark Templar Saga series of novels. Although Mengsk sees himself as a benevolent dictator, he is shown to be just as harsh as his predecessors.
Mengsk's actions during his campaign against the Confederacy make an enemy of Jim Raynor, one of the Sons of Korhal commanders. After Mengsk betrays other members of his command staff and reveals his real objectives of obtaining ultimate power, Raynor deserts and forms a resistance movement to the Dominion, labeled Raynor's Raiders. Described in the novels as a small army primarily consisting of members from Raynor's former colonial militia, the Raiders use the hijacked former flagship of the Sons of Korhal, the Hyperion, as their base of operations. In Queen of Blades, the group is described as being amongst the most wanted fugitives and rebels of the Dominion. The player will assume the role of Raynor in leading the group in StarCraft II.
Depiction
The Terrans are displayed as standard humans, and are often seen in-game in powered combat suits and with other war machines such as futuristic tanks and space battlecruisers in use by their militaries. Some Terrans are even displayed with cybernetic implants. Human behavior in the fictional history presented in StarCraft's manual also points to the Terrans having the ability to access and deplete a planet's natural resources at an "alarming" rate. The Terrans are also noted in the backstory of the series as having a developing psionic potential. This psionic potential is what entices the Zerg to attack the Terrans, in hope of incorporating these traits into the Zerg gene pool. This psionic element is mirrored in Terran military technology through the ghost agent. Established as one of the iconic parts of StarCraft, ghost agents are Terrans who are born with ranging psionic abilities—from simple telepathy to advanced powers such as telekinesis—that are then located by the military and put through an espionage training regime that can cost them their lives. In-game, the unit of a ghost is equipped with a cloaking device and is designed for scouting and designating targets for nuclear strike, but has been developed further through the lore of the series to the extent that the StarCraft: Ghost sub-series was created, specifically focusing on the life of a ghost agent.
Appearances
The player is first fully introduced to the Terrans in Episode I of StarCraft. For a number of years before the game begins, the Confederacy is shown to be fighting a slowly losing war against the Sons of Korhal. When the Zerg and Protoss make their existence known, the pace of the war quickly changes. The player, accompanied by Jim Raynor, joins up with Arcturus Mengsk and the Sons of Korhal, and helps bring about the fall of the Confederacy by using Confederate technology to lure the Zerg into destroying the Confederate capital Tarsonis. As a result of the brutal tactics used by Mengsk, Raynor abandons Mengsk and his newly formed Dominion, instead searching for Mengsk's second-in-command Sarah Kerrigan, who was captured by the Zerg during the Tarsonis battle. Raynor is unsuccessful in rescuing Kerrigan, but meets Zeratul and Tassadar and consequently becomes an ally to the Protoss. Raynor's forces assist the Protoss in defending their homeworld from the Zerg and in destroying the Zerg Overmind in the game's conclusion.
In Brood War's Episode V, the player takes the role of a captain in a UED expeditionary force, sent to pacify the wartorn sector after the discovery of the Zerg and Protoss makes its way to Earth. The UED force meets success in its initial battles, quickly bringing the Dominion to its knees and taking captive a new Overmind growing to replace the one killed by Tassadar. However the UED fail to capture Mengsk, who allies with Raynor, Kerrigan and the Protoss templar Fenix. The UED is slowly beaten back by this mutual alliance, and although Kerrigan betrays her new allies, her Zerg forces eventually annihilate the UED fleet. Regrouping his surviving forces, Mengsk begins to reconstruct his empire, although he is still opposed by Raynor and his troops.

Zerg

The Zerg Swarm are a race of fictional insectoids and the overriding antagonists of the StarCraft series. Operating as a hive mind, the Zerg strive for genetic perfection by assimilating "worthy" races into their own, creating numerous different strains of Zerg. Unlike the Protoss and the Terrans, the Zerg do not use technology, instead using assimilation of other species and directed mutation to develop traits to match such technology. As with the other two primary races, the Zerg are the subject of a full campaign in each of the series' real-time strategy video games. Zerg units are designed to be cheap and fast to produce, encouraging players to overwhelm their opponents with sheer numbers. Since the release of StarCraft the Zerg have become a video gaming icon, described by PC Gamer UK as "the best race in strategy history". The phrase "zerging" has entered video gaming jargon to describe using many low-cost and weak units to overwhelm an enemy.
Society
The Zerg are a collective consciousness of a variety of different races assimilated into the Zerg genome. The Zerg are originally commanded by the Zerg Overmind, a manifestation of this hive mind, and under the Overmind's control the Zerg strived for genetic perfection by assimilating the favourable traits of other species. After a species has been assimilated into the Swarm, it is mutated towards a different function within its hierarchy, from being a hive worker to a warrior strain. StarCraft's manual notes that some species bear little resemblance to their original forms after just a short time into assimilation. The Overmind controls the Swarm through secondary agents called cerebrates. Cerebrates command an individual brood of Zerg, each with a distinct tactical role within the hierarchy. Cerebrates further devolve power through the use of overlords for battlefield direction and queens for hive overwatch.
The vast majority of the Zerg do not have any free will as they are genetically forced to obey the commands of those further up the Zerg hierarchy, although they are sufficiently intelligent to form strategies and work as a team on the battlefield. Despite this, the average Zerg has no sense of self preservation. Along with the Overmind, the cerebrates are the only Zerg with full sapience, each with its own personality and methods, although they too are genetically incapable of disobeying the Overmind. The Overmind also possesses the ability to reincarnate its cerebrates should their bodies be killed, although Protoss dark templar energies are capable of disrupting this process. If a cerebrate is completely dead and cannot be reincarnated, the Overmind loses control of the cerebrate's brood, causing it to mindlessly rampage and attack anything. As a result of the Overmind's death in StarCraft and the subsequent destruction of a new Overmind in Brood War, Blizzard Entertainment's Chris Metzen revealed that the surviving cerebrates perish as they are genetically incapable of surviving without their master, leaving the infested Terran and prize of the Overmind, Sarah Kerrigan, in complete control over the Swarm.
Depiction
The backstory for the series describes the original Zerg as small larvae, the "most insignificant lifeform" on their homeworld Zerus. The Xel'Naga are responsible for manipulating the evolution of the Zerg, allowing the larval Zerg to parasitically merge with other creatures, taking control of their host's nervous systems. From here, the Zerg can mutate the host and add its DNA to the Zerg gene pool for other Zerg larvae to mutate into. This method of assimilation means that there is no distinctly typical Zerg, rather many different strains and breeds of Zerg, each based on the original core genus. However, the style of the Zerg is consistent, with breeds using a carapace for armor, and using spines, claws and acids for attacking enemies. Each strain serves a distinct role and possesses the traits necessary to fulfil its function. Zerg colonies also exhibit similar roles, with each structure built within a colony essentially making up an organ in a larger lifeform. Zerg colonies produce a carpet of bio-matter referred to as the "creep", which essentially provides nourishment for Zerg structures and creatures. The Zerg are also shown to be highly dependent on their command structure: if a Zerg loses its connection to the hive mind, it becomes completely uncontrollable and attacks anything in sight.
Appearances
In StarCraft, the Zerg are obsessed with the pursuit of genetic purity, and are the focus of the game's second episode. With the Xel'Naga–empowered Protoss targeted as the ultimate lifeform, the Zerg invade the Terran colonies in the Koprulu sector to assimilate the Terrans psionic potential and give the Zerg an edge over the Protoss. Through the actions of the Sons of Korhal, the Zerg are lured to the Confederate capital Tarsonis, where they capture the psionic ghost agent Sarah Kerrigan and infest her. Returning to the Zerg base of operations on Char, the Zerg are attacked by the dark templar Zeratul, who accidentally gives the location of the Protoss homeworld Aiur over to the Zerg Overmind. With victory in sight, the Overmind launches an invasion of Aiur and manifests itself on the planet. However, at the end of the game, the Protoss high templar Tassadar sacrifices himself to destroy the Overmind, leaving the Zerg to run rampant and leaderless across the planet.
The Zerg return in Brood War initially as uncontrolled indisciminate killers. Through the early portions of Brood War, Sarah Kerrigan is at odds with the surviving cerebrates, who have formed a new Overmind to restore control of the Swarm. Through allying herself with the Protoss, Kerrigan strikes at the cerebrates, causing disruption of their plans. Eventually, the UED fleet takes control of Char and pacifies the new Overmind with drugs, putting the cerebrates and most of the Zerg under their control. Kerrigan retaliates by allying with the Dominion and the forces of Jim Raynor and Fenix, regaining the ground lost to the UED. However, she later betrays this alliance, dealing long-term damage to her allies' infrastructures. Proceeding to blackmail Zeratul into killing the new Overmind, Kerrigan's forces destroy the remnants of the UED fleet, giving her full control of the Zerg and establishing the Swarm as the most powerful organization in the sector.