When the Survivors need guidance, they consult a wise oracle known as the Imperator.
After Will escapes from the prison, Atem tells him to go and listen to the Imperator's message. When Ava objects to this (thinking that Nikola Tesla was The Key, and that the message was only meant for him), Atem cryptically replies that she has underestimated Will.
Once aboard The Ark (where the Imperator now resides, either rescued from the Broken Land or the Watcher Base), Will enters a room where a man is playing chess and a little girl is sitting on the ground. After a moment of Will asking the man where the Imperator is, the little girl stands up and gives Will the message (due to the content of what she says, it is obvious that the little girl is indeed the Imperator).
The Imperator says that it was right of Atem to believe in Will, and she states that he is indeed The Key. She thens proceeds to say that the Watchers have opened a doorway back to Earth, and that their hold over humanity grows stronger. The Imperator then says that the events set in motion by the Watchers must be stopped, and their doorway must be closed. To do this, she says that Will must climb "their Tower," and that he must face The Dweller. Her final words are that if Will does not do these things, all will be lost.