StarCraft: Brood War was released in 1998.
Developed by Blizzard Entertainment and Saffire, Brood War is the official expansion pack for the original StarCraft. It continued the three-way conflict after the base game and added new campaigns, units, technologies, music, maps, and multiplayer content.
Brood War introduced major story developments involving the United Earth Directorate, Sarah Kerrigan, the Zerg, and the Protoss. Its three new playable units for the original factions became important parts of competitive strategy: the Terran Valkyrie, the Protoss Corsair, and the Zerg Lurker.
The expansion is often associated with 1998 because it followed the original game within the same calendar year. It is also frequently discussed separately from StarCraft II, which began a new trilogy more than a decade later.