Sector X is a sub-sector consisting of many locations. It was later inhabited by millions of Zerg and later by Jim Raynor and Tassadar. It later had a Protoss extraction team including Xel'kraeas. It consisted of the four Serectian planets and other places. Tassadar harnessed X21 - 21BA's power for the Psi Storm. He later needed NOVA20-X to blare out the Dark Templar for their elusive cloaking.