Father Philip Callaghan (played by Patrick Fitzgerald) - A Roman Catholic priest and linguist from Ireland. Philip is a compassionate man who believes that virtue and faith are the best weapons against evil, but he also struggles with sexual temptation and lapses in faith. His brother was killed in an IRA car-bombing, which destabilized his beliefs. He appeared only in the first two seasons of the series in a recurring role, but returned for a 2-part episode in the final season.