Glenn Martin Christopher Francis Quinn was an Irish actor, best known for his portrayal of Mark Healy on the 1990s family sitcom Roseanne and his role as the half-demon Allen Francis Doyle on Angel, a spin-off series of Buffy the Vampire Slayer.

Francis Allen Doyle is a fictional character created by Joss Whedon for the television series Angel. The character was portrayed by Glenn Quinn. Doyle is a seer who receives prophetic visions from The Powers That Be, usually of people in peril. Half-human, half-demon, his demon heritage allows him to manage them without suffering any permanent damage. His half-Brachen demon physiology grants him the ability to shift from normal human to demonic appearance, in which he has heightened sense of smell and superior strength, speed, stamina, and dexterity, the last of which allows him to twist his head around in such a manner as to fake a broken neck. However, Doyle rarely used his Brachen powers, preferring to remain human, thus limiting his usefulness in a fight.