Ada Wong is the pseudonym of an otherwise-unnamed red-clad, secret agent of Chinese heritage. Initially a private agent, Ada was drawn into the intrigue and treachery that is the corporate world when she was recruited by a rival company to participate in their activities against their primary rival, Umbrella, and later moved to another. Ada's past life before 1998 is a complete mystery. Her ethnicity and nationality are left unconfirmed, and when and where she was born are also unknown. Even her birth name is not believed to be real.
She was sent to infiltrate the Arklay Laboratory, hidden beneath a mansion in the Arklay Mountains and was romantically involved with the new head researcher, John Clemens, as a means to steal intelligence for her company. At some point, she worked for Derek C. Simmons, who became infatuated with her. After his decision to destroy Raccoon City as a result of its t-Virus outbreak, she left him and the job. Simmons, who had already gained strong feelings for Ada, eventually used Carla Radames in an experiment to clone Ada for himself. Ada found out all about his evil plan and her evil twin and took the situtation in her hands which she successfully terminated.