Rasputin is a Warmind built to defend Earth during the Collapse. He is the only Warmind known to have faced The Darkness and survived. He protects something deep below Old Russia that the Fallen House of Devils desire to retrieve. After a mission by a Guardian, he also began connecting to AI that were formerly controlled by other Warminds across the Solar System.
In The Buried City, the player's Ghost mentions that "He's everywhere now" at the end of the mission while analyzing a machine.
After the Fallen House of Devils reactivated SIVA, Lord Saladin hinted that the Vanguard didn't know Rasputin's true intentions, revealing that Rasputin had attempted to prevent the Iron Lords from deactivating SIVA centuries ago and that "Rasputin hasn't been just a Warmind for a long time". While his motivations are unclear, Rasputin may have wanted SIVA in order to create a physical body.