In the most recent episode, Katherine uses Elena's body as a passenger. Elena is a vampire, and therefore a supernatural being. Can a Traveler take over a supernatural being? I was under the impression that they can only take over humans. Also, when the travelers first appeared, they were looking for Katherine to kill her. Is that no longer their plan? Were they looking for Katherine because her daughter Nadia was searching for her? Are are the travelers still wanting Katherine dead and Nadia is straying from their purpose for her own gain (to reunite with her mother)??