SIVA
SIVA is a lost Golden Age self-assembling nanotechnology capable of building anything. Long ago, the Iron Lords found the plague known as SIVA. SIVA has the power to create anything, and the Iron Lords wanted to use SIVA to rebuild ships and colonies that were lost or destroyed during The Collapse. They went to Rasputin's bunker in Site 6, and tried to communicate with the Warmind, but he thought they were hostiles. He released SIVA on them, and the Iron Lords had to sacrifice themselves to contain the virus. SIVA was locked away and forgotten. Until now.......
SIVA-infected Fallen are the main Enemy Faction of the Rise of Iron expansion. The Fallen House of Devils uncovered the SIVA virus in the Plaguelands, and the Splicers augmented themselves with it to unlock special abilities.
