Hunter Perry (Kyle Bornheimer) was a CIA agent who began feeding information to The Ring, which led to the deaths of several government agents and innocent civilians. Initially he sold his secrets through a Russian information broker named Anatoli Zevlovski before betraying and murdering him in order to contact The Ring directly rather than work with an intermediary.
As part of his final spy exam, Chuck was assigned to shadow Anatoly and determine the identity of his CIA contact. After his identity was revealed, Shaw determined that with Zevlovski dead, Perry needed to be eliminated as well, and instructed Sarah to order Chuck to make the hit as his "Red Test". When cornered, Perry attempted to escape by playing against Chuck's hesitation to kill, and was later gunned down by Casey to make it look like Chuck had completed the assignment himself.
The next episode reveals that Perry had smuggled intelligence by swallowing it, and The Ring retrieved it from his dead body in the DNI headquarters. The chip he took contained surveillance video of Sarah, in her own "Red Test", killing Shaw's wife, which helps explain why The Ring stopped trying to kill Shaw. Seen in: "Chuck Versus the Final Exam"