Thorfinn Drusus Alpin McGonagall (7 April 1879–15 March 1979) was the father of Minerva and Einar McGonagall in the Epithalamium series of stories by Squibstress. A descendant of an old Scandinavian-Scottish pure-blood family, Thorfinn was a wealthy and learned wizard and the author of several books on wizarding sociology and magical-Muggle relations. He was first married to Morrigan McGonagall (née MacLaughlin), who was the mother of Minerva and Einar McGonagall. Many years after Morrigan's death in childbirth, Thorfinn married Elisabeth Bones (née Cadwallader), the widowed mother of Amelia and Edgar Bones.