Bertram (The Lamentation Cipher)

"Bertram" was the name that Charlotte Pollard gave to a Viyran otherwise known as the Rogue Viyran.

The Lamentation Cipher
Bertram 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)

In the 21st century
The Rogue Viyran dispersed Charley and Robert's pod in order to cushion their arrival and ensure their survival. His own molecules were also dispersed, but he managed to recombine himself at Department 001 and rejoined Charley and Robert, telling them that the Identical Men that confronted them were too dangerous to take on. (AUDIO: Embankment Station)