Dan Mason, codename Spy, is an assassin for hire. He is the parallel version of Dan Mason from the original timeline.
Dan's family are Spy's working for TF Industries, starting with his grandfather and later his father. At some point in the 2000s, he began working as a Spy and operated on the side of both the Combine and the Resistance, depending on who had the better deal. Once the Combine were defeated, he became a hired mercenary, although would take up any job depending on what was in return for him.
Working for the Administrator
The Spy began working for a man known as "the Administrator", who is the brother of the late Wallace Breen. The Administrator wanted control of City 17, which was under that of Jackie Robertson. The Spy kidnapped Jackie's daughter Hannah Robertson by posing as Hannah's protector Nathan Johnson, by using the highly technical Spy disguise. Nathan managed to rescue Hannah however, which led to the arrest and imprisonment of the Administrator. The Spy managed to evade capture and later went to meet his friend and partner in crime the Heavy, in which he lamented that Nathan is familiar.