StarCraft 64

The story of StarCraft is presented through its instruction manual, the briefings to each mission, and conversations within the missions themselves, along with the use of cinematic cutscenes at key points. The campaign is split into three episodes, each allowing the player to command one of the game's three races. In the first segment of the game, the player and Jim Raynor are attempting to control the colony of Mar Sara in the wake of the Zerg attacks on other Terran worlds. After the Confederacy arrests Raynor for destroying Confederate property, despite the fact that it had been infested by the Zerg, the player joins Arcturus Mengsk and the Sons of Korhal.

Raynor, who is freed by Mengsk's troops, also joins and frequently accompanies the player on missions. Mengsk then begins to use Confederate technology captured on Mar Sara to lure the Zerg to Confederate installations and further his own goals. After forcing Confederate general Edmund Duke to join him, Mengsk sacrifices his own second-in-command, Sarah Kerrigan , to ensure the destruction of the Confederacy by luring the Zerg to the Confederate capital Tarsonis. Raynor is outraged by Mengsk's true aims of obtaining power at any cost and deserts, followed by the player, taking with them a small army of the former colonial militia of Mar Sara.

Mengsk reorganizes what remains of the Terran population into the Terran Dominion , crowning himself as emperor. The second campaign reveals that Kerrigan was not killed by the Zerg, but rather is captured and infested in an effort to incorporate her psionic traits into the Zerg gene pool . She emerges with far more psionic powers and physical strength, her DNA completely altered. Meanwhile, the Protoss commander Tassadar discovers that the Zerg's cerebrates cannot be killed by conventional means, but that they can be harmed by the powers wielded by the heretical dark templar .

Tassadar allies himself with the dark templar prelate Zeratul , who assassinates Zasz , one of the Zerg's cerebrates in their hive clusters on Char. The cerebrate's death results in its forces running amok through the Zerg hives, but briefly links the minds of Zeratul and the Zerg Overmind , allowing the Overmind to finally learn the location of the Protoss homeworld Aiur, which the Overmind has been seeking for millennia. The main Zerg swarm promptly invades Aiur, while Kerrigan is dispatched to deal with Tassadar, and despite facing heavy Protoss resistance, the Overmind is able to embed itself into the crust of the planet. The final episode of the game sees Aldaris and the Protoss government branding Tassadar a traitor and a heretic for conspiring with the dark templar.

The player (later retconned to be Artanis ) initially serves Aldaris in defending Aiur from the Zerg invasion, but while on a mission to arrest Tassadar, the player joins him instead. ) The dark templar prove their worth when they use their energies to slay two more of the Zerg cerebrates on Aiur, and the Conclave reconciles with them. Aided by Raynor's forces—who sided with Tassadar back on Char—the Protoss break through the Overmind's weakened defenses and destroy the Overmind's outer shell, but take heavy casualties in the process. Tassadar channels his own psionic energies in combination with those of the dark templar through the hull of his command ship and crashes it into the Overmind, sacrificing himself in order to destroy it.