Star Wars: Empire at War: Forces of Corruption is an expansion pack for the original game. It was released in October 2006, and became available on Steam in 2010, as part of Star Wars: Empire at War Gold Pack.
The expansion adds many new units, abilities, heroes, planets, and a new faction, the Zann Consortium. A new campaign follows Zann's rise to power, and introduces his crime syndicate as a new rival to both the Empire and Rebellion.
Characters, things, and events that relate to the Zann Consortium originate mostly from this game itself, instead of from prior Star Wars expanded-universe literature.