Mr Warren was a Muggle and the father of Muggle-born witch Myrtle Elizabeth Warren, who attended Hogwarts School of Witchcraft and Wizardry, and was killed by a Basilisk there on 13 June, 1943. He planned to go to the school with his wife soon after this tragedy occurred. His daughter's ghost, known as Moaning Myrtle, resided in the girls' bathroom at Hogwarts.