Roy is the leader of a group of ghoul dissidents living inside the Warrington Metro tunnels. They have decided to try to force Mr. Allistair Tenpenny into letting them move into his tower. As Mr. Tenpenny has refused, Roy Phillips wants to take matters into his own hands.
As an ex-cop with a no-nonsense, black-and-white world view that has carried over into his new life as a ghoul. He has come to terms with his ghoulhood and yet demands that humans treat ghouls with respect. He has no patience for bigots. Bessie Lynn is his ghoulfriend.
Depending on how the player handles the quest Tenpenny Tower, he may reside there.
If you get Roy in to the tower peacefully, he will eventually kill everyone inside (besides the ghouls). This includes Allistair Tenpenny, Herbert Dashwood and the security personnel.
If the player completes the Tenpenny Tower quest before doing The Power of the Atom, and chooses to destroy Megaton in the latter, Roy will have a short discussion with Burke on Tenpenny's balcony. After expressing shock at Burke's ability to infiltrate the tower, he warms up considerably when he learns of Burke's plan to blow up "that smoothskin shithole".
Upon letting the feral ghouls into the Tower, it is possible that Roy will be killed by security personnel.