Oksana Volkova is an agent of the GRU.
One might almost call her a spymaster for the way that she spends most of her time manipulating the people she encounters to further her schemes. One blurb regarding her described her as "a ruthless double-dealing Soviet Army intelligence officer" and considering her actions in these series of actions, that might have been a bit kind.
The series is subtitled Red Army Spies and the Blackrobes. The latter term refers, in my opinion, to the black garments routinely worn by Catholic priests and specifically to those of the Society of Jesus, aka Jesuits.
Formally, when we first meet her, the year is 1956 and she is Captain Oksana Volkova of the Chief Intelligence Directorate of the General Staff of the Red Army. She has already been an officer in that division for a few years and had earned her promotions. Now she had come up with an audacious plan that she boldly took to the Director and gotten permission to put it into action.
Interestingly, while the stratagem she devised would take place in the United States and play with of two powerful subject matters, politics and religion, her overall target is the unseating on the newly selected Soviet Premier, Nikita Khrushchev. Her boss at the GRU, General Michail Andreyevich Kalenko had been fearing the rise of this man for some time but had hoped that the men in charge after Stalin's death, Molotov, Malenkov, and Beria, would stop him but it was not to be. That is when Volkova's plan was authorized by him.