Agent Rivera is one of the Hydra agents embedded within S.H.I.E.L.D. In 1989, Hydra scientist Dr. Werner Reinhardt was secretly given a pardon by Undersecretary Alexander Pierce, himself a Hydra operative, and agents Rivera and Hauer were sent to the facility known as "the Rat" to retrieve him. The two agents then took Dr. Reinhardt back to Austria to resume his studies. Agent Rivera's current status is unknown.