The base served as a secret research facility for the Terran Dominion. It was overseen by Dr. Emil Narud, who was developing protoss-zerg hybrids, supposedly as weapons for Emperor Arcturus Mengsk. Unknown to the Dominion, however, Narud was a servant of Amon, a fallen xel'naga who intended to use the hybrids to wipe out all life in the universe.
The hybrid lab itself was built on top of a series of xel'naga temples. These temples were protected by a band of Tal'darim protoss who worshiped Amon and served as Narud's elite guard.
At some point between the end of the Brood War and the start of the Second Great War, the resurrected UED Admiral Alexei Stukov was brought to Skygeirr station, where he was tortured and experimented on by Narud. During this time, Stukov learned about Narud's true identity, as well as his connection to Amon. Eventually Stukov escaped, and contacted Sarah Kerrigan.
With Stukov's aid, Kerrigan and her Swarm attacked Skygeirr Platform, first destroying the surface defenses, then invading the hybrid lab itself. There, the zerg defeated the Dominion and Hybrid forces, and pursued Narud to the lower levels where they encountered the Tal'darim. At the same time, Narud attempted to kill Kerrigan with a null zone, which he created by drawing power from the xel'naga temples. Stukov, however, managed to deactivate all the temples, despite the efforts of the Tal'darim to stop him. This weakened Narud and enabled Kerrigan to kill him, though she herself nearly died in the process.
Click here for a walkthrough covering the Skygeirr Missions.
