Evil terrorist Anya Vitez
Anya Vitez (Bojana Novakovic) is the hidden main villainess from "Jack + Kinematics + Safe Cracker + MgKNO3 + GTO," episode 5.05 of MacGyver (airdate January 15, 2021).
Anya Vitez was introduced as an Interpol agent who assisted the Phoenix group in their search for notorious terrorist Tiberius Kovac, as Phoenix was in Zagreb on the case following the sudden death of their longtime friend Jack Dalton, who had been on the case for a long while. After pointing a gun at Russ Taylor due to his known history, Vitez joined the group in their mission, which led them to Tibor Babic, who was introduced as an ally of Kovac.
In actuality, Tibor revealed to Angus MacGyver (after recognizing him due to his handiwork) that he and Jack were working together to take down Kovac, and following an ambush that saw one of their gunmen captured, Tibor gave another message to MacGyver from Jack: remember their "manniversary" in Vegas. After MacGyver remembers the details of their trip, it leads them to the realization that Kovac is a "mirage" and not a real person; though the captive gunman--the only lead--ended up shot and killed by a sniper.
MacGyver left with Russ and Desi Nguyen to pursue the sniper, only for the group to learn that they were part of a military group led by Vitez, who was revealed as a villainess with their discovery. Vitez later appeared with one of her henchmen and held Wilt Bozer and Riley Davis at gunpoint, with the villainess revealing that she was Kovac. After shooting Bozer (non-fatally) and abducting both him and Riley, the evil Vitez revealed that her operation was mainly cash-for-chaos, and she ordered Riley to activate her laptop under the threat of killing Bozer if she refused.
The villainous mastermind used Riley's laptop to set up Jack as Kovac, planting a money trail that would lead to Jack, while also portraying the Phoenix group as having been killed trying to cover up Jack's crimes. While doing so, Vitez mocked Riley with a revelation that Jack told her prior to the raid at a compound that he couldn't wait to return home and have a greasy pizza with Riley--a cryptic reveal that Vitez killed Jack to cover her tracks. At that moment, MacGyver appeared and and dropped an explosive as a smoke screen for Desi to arrive and hold Vitez at gunpoint. The villainess boasted that it would be her word against theirs regarding her actions, only for Riley to reveal that the passcode she entered turned on the laptop and a video camera, which recorded Vitez's confession. Vitez was arrested, but not before Riley lashed out at the villainess for killing Jack, who was a father figure to Riley.