Rick Mason served as a mercenary with a specialization in the non-lethal handling of superhumans, having grown up exposed to advanced technology necessary for such tasks as the son of the criminal inventor Phineas Mason, better known as
Tinkerer. Mason was once hired to kill an alleged mole code-named "Vitamin" from the
Central Intelligence Agency in
Berlin. In an attempt to kill him, Mason blew up a hotel, but he was under observation by Michael Rossi and
Carol Danvers, who tracked him across the city. Mason escaped using one of his father's devices to become invisible. His upbringing in New York City brought him into contact with many criminals due to his father's occupation. Ill at ease with wrong-doers, the Agent sought a path in life other than aiding others in perpetrating crimes. Becoming a mercenary the Agent worked for
S.H.I.E.L.D. though was later hired by the
British government to prevent the super team China Force from overthrowing their rule of
Hong Kong. Returning to S.H.I.E.L.D., he was required by Nick Fury to undertake a similar mission in
Costa Brava involving American-backed rebels. The Agent discovered that one of his former teachers, Teng Yun-Suan, was responsible for both of these incidents. Yun-Suan met death at the Agent's hands. As a freelance mercenary with a specialization in non-lethal superhuman handlings, he assisted Nick Fury involving superhuman mercenaries. The Agent remained on good terms with his father despite the latter making a living in a field he did not approve of. The
Corporation used this to their advantage and kidnapped the Agent to force the Tinkerer to work for them. Mason encounters
Luke Cage and
Dakota North and the three defeat the Corporation. However, Mason was apparently killed later on after which his activities as the anonymous Agent were public knowledge. ==Powers and abilities==