Katherine, surviving inside Elena’s mind, works with her daughter and a Traveler witch named Mia to make the possession permanent.
Katherine forces Matt Donovan to help her mimic Elena’s mannerisms and history so she can go undetected. [S5E12] The Devil Inside
Matt throws a welcome-back party for , but the celebration is short-lived. Katherine, surviving inside Elena’s mind, works with her
Katherine (as Elena) coldly dumps him, telling him they are over for good. surviving inside Elena’s mind