Bertram (The Lamentation Cipher)

 was a Viyran who spoke differently to the other members of his species and was light on his feet.

He told Charlotte Pollard that the Viyrans didn't know much about the Ever-and-Ever Prolixity. He knew of the Lamentation Cipher. (AUDIO: The Lamentation Cipher)

He infected Charley with a virus that would reboot the Viyrans. He allowed her to escape so it would incubate in her and make it more virulent. (AUDIO: The Viyran Solution)