A Watcher, her cover is that of an FBI agent. Her assignment is the immortal, Matthew McCormick, whose cover is also that of an FBI agent.
Note: Her name is a humorous nod to Fox Mulder and Dana Scully, the protagonists in The X-Files television series. Scully and Mulder, along with Caligula and Incatatus, were once jokingly mentioned by Methos in the Highlander episode Indiscretions as an example of a 'great team.'