Pyerpoint
Pyerpoint was a High Archon on the Rock of Judgement. Secretly, he used his connections to become the head of a large criminal empire. When acting in that capacity, he sometimes used the alias "Sentinel".
When Xais was alive, they were allies, with Pyerpoint directing Xais against certain targets to eliminate his criminal and business rivals. She promised Pyerpoint to use her psychic powers to imprint his brain patterns in helicon, making him immortal. In fact, she planned to double-cross him in her campaign to kill all "Normals", as it was actually impossible for her to share the secret of her immortality with him as he lacked psychic powers of his own. After Charlie Nisbett killed the body Xais was controlling through her helicon death-mask, Pyerpoint took the mask and fled. Romana II chased him, and he forced the mask onto her.
Later, Romana was able to free herself after the Doctor affirmed that it was impossible for Xais to share her immortality with Pyerpoint. Restricted to the mask once again, Xais convinced Pyerpoint she still could store his mind in helicon and had him put on her mask to share the secret, Pyerpoint so desperate to believe her that he put the mask on. While struggling for control, he was killed by one of the station's robots, which Pyerpoint had ironically programmed earlier to kill any intruders. (PROSE: The Romance of Crime, AUDIO: The Romance of Crime)
