New mystery! What is the Imminently Deceased?

At first I thought it was a time travel thing, that Sollux was hearing the voices of the trolls that died as a result of the game, the voices transported back through time. But then I went back and found that Karkat’s coding handbook was for the Imminently Deceased as well. I’m guessing it’s some sort of proto-god type thing, not like regular trolls but not the almighty, something powerful that dabbles in what the trolls are doing.