Ghost

Ghosts are covert operatives in the StarCraft universe. They are known for their psionic powers and ability to become invisible.

Ghost Training
Ghosts are always psychic Terrans, and they use this ability to enhance their strength, speed and endurance. They are generally trained as commandos and assassins, appearing and striking suddenly and silently. In a particularly infamous action, they used these abilities to execute Angus Mengsk, the father of Arcturus Mengsk, in order to shut down the rebellion of Korhal IV. His head was never found.

Telepaths who could be useful to the Terran armed forces (either as Ghosts or performing other roles) are usually tracked down by "Wranglers", mildly psionic agents whose powers are generally only useful for finding other telepaths at close range. They can use equipment to help them in their search, but the equipment is itself limited.

Many sources indicated that the Terran Confederacy used to take children showing signs of psionic power and put some or all into the Ghost program. It is unknown what happened to children who were either not selected for this program or who didn't graduate.

Ghosts and other Terrans have a "Psi Index" rating, which scales up to PI10 (the highest rating). Most humans are PI2 or less, whereas most Ghosts are PI5 or more. At least some psychics of PI8 can use telekinesis. The PI ratings of Wrangler Malcolm Kelerchian and Nova are known; 3.5 and 10, respectively.

The Terran Confederacy decided to limit Ghosts through at least four methods.

The first is a psi-dampener, also known as a neuro-adjuster (rumored to also suppress or reshape a disloyal Ghost's memory) which weakens their powers. Mindwiping was (according to Arcturus Mengsk) introduced by the Terran Confederacy as a result of Kerrigan's defection from the Confederates, but according to StarCraft: Uprising the treatment was being used before she left the Confederacy. Naturally Mengsk didn't remove this horrible training technique.

The second are neural processing treatments. The third are aggression inhibitors (which prevent a Ghost from attacking his/her superiors) and the last is Ghost conditioning, a powerful form of hypnosis which restricts the use of their psionic abilities. This conditioning was so powerful thateven after Sarah Kerrigan was infested, she did not immediately lose this psychic hindrance. The wide array of anti-psionic control methods may indicate that Blizzard Entertainment did not have a clear vision of how telepaths were controlled in the StarCraft universe.

Ghosts are given some training in psionics, but not much. Their abilities are generally limited to personal augmentation (as detiled above) and mind-reading.

Ghosts (and their instructors) frequently use "psi-screens", devices (introduced in StarCraft Ghost: Nova) which prevent telepaths from reading their minds and also cancels out a telepath's mind-reading abilities if worn by a telepath. Psi-screens, which are so rare that it was harder to acquire than a nuke from the former Confederate army, come in various versions, including touch-activated ones (which are lower-quality). Higher-ranking people get to wear higher-ranking devices. The device is harmful, however, if worn for more than seven hours, causing memory loss and (possibly) brain damage.

The Ghost Academy
Ghosts receive an average of four years of training at the "Ghost Academy" - much of their training comes from non-psychics, such as Mr. Rumm and Sergeant Hartley. Attempts to train Ghosts faster simply results in "bad" Ghosts. Ghosts who aren't proficient enough to pass their training are "eliminated". Nova made a record during her training; it only took her two-and-a-half years to pass her training despite her numerous disadvantages. She was the first Ghost to be put through a "graduation exercise".

The first Ghost Academy, also used to research Zerg, was on Tarsonis but this was destroyed by the Sons of Korhal in an action which made their leader, Arcturus Mengsk, notorious. It was later rebuilt. The second Academy was then destroyed during the Sons of Korhal and Zerg invasion of Tarsonis during the latter part of StarCraft Episode I and the early part of StarCraft Episode II. It was later rebuilt on Ursa by the Terran Dominion.

Other Government Training
The Terran Dominion has adopted this program, but perhaps choose their subjects differently. The Kel-Morian Combine also uses Ghosts, but it is unknown if the Umojan Protectorate does as well.

The United Earth Directorate has used Ghosts, even though its predecessor the United Powers League tried to wipe out mutants, including psychics.

The UED seems to have used psychic scientists who had not received Ghost training in their efforts to control the Zerg.

Game Unit
Ghosts are issued with a Hostile Environment Suit with a cloaking device powered by a personal Moebius fusion reactor and psionic powers (which stimulate receptors in the Ghost's suit). A Ghost can attack while invisible. While it is difficult to detect an invisible (cloaked) Ghost, it is possible.

Ghosts are also issued a C10 25 mm canister rifle. In addition to powerful, long-ranged anti-personnel rounds, it can fire a number of specialized grenades and missiles, such as the lockdown missile.

In addition, Ghosts are frequently augmented with cybernetic surgery, especially their eyes. These cybereyes enable them to see objects much further than a regular human could.

Nuclear Strike
Ghosts are equipped with a target painting laser device. By using it on a site for 10-15 seconds (real time) a ghost can provide targeting information to a friendly nuclear silo, enabling it to fire a tactical nuclear warhead. The Ghost is often within the blast radius and dies unless he or she has received the above optical surgery to increase vision range. In addition, the Ghost is completely vulnerable while using the targeting laser, and can easily be killed, which will result in an abortion of the nuclear launch. All forces in the region will detect the launch of the nuke (receiving the message "Nuclear Launch Detected" immediately as the Ghost uses the laser) and if they can see the target site, the target painting laser (a flashing red dot) is also visible. These two events serve to alert the enemy as to Ghost's presence and general whereabouts. Cloaking helps provide a degree of protection for the ghost, but is no guarantee when put against the aforementioned obstacles, as players will frequently bring whatever detection resources available to bear on the telltale red dot and therefore the nearby Ghost.
 * Starting ability
 * Requires: Arm Nuke

Lockdown
This special missile can shut down machinery for a short period of time, but requires energy from the Moebius reactor to do so. The lockdown missile may be an electromagnetic pulse weapon.
 * Cost: 200\200
 * Researched at: Covert Ops
 * Energy Cost: 100

Personal Cloaking
This enables the Ghost to cloak.
 * Cost: 100\100
 * Researched at: Covert Ops
 * Energy Cost: 25 (+ 1 more per second to remain cloaked)

Upgrades

 * Infantry Weapons
 * Infantry Armor

Ocular Implants
Increases Ghost sight to 11.
 * Cost: 100\100
 * Upgraded at: Covert Ops

Moebius Reactor
Increases maximum Ghost energy by 50.
 * Cost: 150\150
 * Upgraded at: Covert Ops

Ghosts in StarCraft: Ghost
StarCraft: Ghost takes place four years after the events of StarCraft: Brood War.

Nova Squadron has recently become part of the Terran Dominion and have been training a Ghost known only as "Nova".

Psionic Powers
Ghosts have the ability to cloak, as in the game of StarCraft. They have access to "psionic vision", which can be used in a variety of ways (for instance to see through walls and to see weak points in armor and security features) and "psionic speed", which roughly quadruples a Ghost's normal speed.

Other abilities may develop later.

Ghost Weaponry
Ghosts appear to be armed differently in StarCraft: Ghost, but the information from various Blizzard sources often conflict with each other.

Ghosts may be armed with the C-20A canister rifle, an improved version of the C-10 rifle they wield in StarCraft. Alternatively, they may wield a trio of primary weapons - an assault rifle which may come attached to a grenade launcher, the BOSON FN92 sniper rifle, and the E11 Lockdown Device, which fires lockdown rounds but has a much shorter range than even the assault rifle.

In StarCraft: Ghost, Ghosts will be armed differently. Ghosts will wield an assault rifle/grenade-launcher combination as their standard weapon. It is less powerful than the C-14 "Impaler" Gauss rifle. This weapon is different from the original C-10 canister rifle. Ghosts may use the cy-blade, a weapon devised using Protoss technology.

Ghosts may carry E16 lockdown grenades, tactical nuke launchers, and the BE3 sticky grenade, depending on the type of mission they are performing. In addition, Ghosts can use "calldowns" to direct artillery of various types against the enemy, such as Siege Tank blasts or even nuclear missiles.

Spectres
In addition to using new technologies, Ghosts can be augmented using terrazine gas, part of General Horace Warfield's Project Shadow Blade. Shadow Blade also uses covertly-collected Protoss technology. While the specifics of exposure to the gas are unknown, it is known to create a genetic mutation in psychics, such as Ghosts.

These Ghosts are transformed into Spectres - shadowy superhuman beings bent on executing the will of their true master.

Famous Ghosts

 * Sarah Kerrigan
 * Nova (of Nova Squadron)
 * Samir Duran
 * Alexei Stukov

Stukov was represented in-game by a Ghost. It's possible that he was a Ghost, was psychic but had not received (extensive) Ghost training, or that was simply used as a placeholder unit. The events of Resurrection IV suggest that he really was psychic.