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 Viyran's 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 viyran. He allowed her to escape so it would incubate in her and make it more viralant. (AUDIO: The Viyran Solution)