The son of Finula McGrath, David McGrath's older sister, Seamus had always looked up to his "Uncle Davey." After Seamus' father left, not long after the birth of his son, David took an active role in Seamus' upbringing. The McGrath's radical views were difficult for many to take, but Seamus refused to take his father's surname for this reason, proudly keeping McGrath. However, the day David returned to Belfast with Machiavella in tow, was the day Seamus knew Uncle Davey had changed. Feeling betrayed, once again, he started a vendetta that ended in blood.