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

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 it's predecessor the United Powers League tried to wipe out mutants, including psychics.

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

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 imfamous 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.

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

Ghosts are issued with a Hostile Environment Suit with a cloaking device powered by a personal Moebius fusion reactor. It is unknown if the cloak is psionic in nature. 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. 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 device.

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.

The Terran Confederacy, however, decided to limit Ghosts through at least four methods - a psi-dampener (rumored to also suppress or reshape a Ghost's memory according to StarCraft: Uprising) which weakens their powers, neural processing treatments, aggression inhibitors (which prevent a Ghost from attacking it's superior officers) and Ghost conditioning, a powerful form of hypnosis which restricts the use of their psionic abilities. This conditioning was so powerful that after Sarah Kerrigan was infested, she did not immediately lose this psychic hindrance.

The Terran Confederacy was rumored to have used Ghosts in a program to attract and even control Zerg.

Nova Squadron has recently become part of the Terran Dominion and have been training a Ghost known only as "Nova". In addition to the above abilities, she also seems to have the ability to see through walls and accelerate at four times normal human speed. These abilities may be created through a combination of psionics and technology, but this has not been conclusively determined.

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 Ressurection IV suggest that he really was psychic.

References

• StarCraft homepage at Blizzard Entertainment
• Battle.net StarCraft Compendium