Carly Klapp (Paige Patterson) was a hidden villainess from Season Two of Quantico. She first appeared in the episode, "Cleopatra," and met Sebastian Chen during the episode's timeline at The Farm. She became a CIA case officer later on, and eventually married Sebastian.
In episode 2.12, "FALLENORACLE," it was revealed that Carly went rogue and joined a rogue faction within the CIA called the AIC, using her marriage to Sebastian as a cover, which also included a phony backstory of being a Senator's aide. Carly's heel turn came when she held Harry Doyle at gunpoint, using the gun she stole from Alex Parrish. After the reveal, the evil Carly demanded that Will Olsen, who has knowledge of the identities of the AIC, be turned over, threatening Harry's life while accusing Alex of being exactly like she is.
Sebastian was taken aback by his wife's reveal, but still pointed his own gun at her, while attempting to talk her down. Despite Carly's claims that she loved Sebastian, the villainess fired a shot at Sebastian, who still managed to shoot Carly in her head, killing her.