Thomas Halloway was the son of a prison warden; his mother died in childbirth. The warden raised Thomas in isolation, in the prison itself, and was instructed by various experts who had taught him "everything." Thomas was also taught by the prisoners, who passed on the secrets of the underworld. When Thomas discovered that one of the prisoners was about to be electrocuted he saved him. For this deed Thomas was dubbed an "angel" by the inmate.
When Thomas reached adulthood he decided to become a private detective, and also adopted the costumed identity of "The Angel" to fight crime. During an adventure in which he saved a 4,000 year old woman, he was given the magical Mystic Cape of Mercury.