Louka's Role in the Separation of Raina and Sergius

Louka sparks Sergius' jealousy by whispering in his ear and telling him that Raina has been unfaithful..... just as he has. She exposes the flaws of both Raina and Sergius, in an attempt to make him see and understand that she is superior, regardless of social class. From start to finish, Louka baits Sergius, and he takes the bait. She makes herself necessary and becomes almost an obsession.