Kes' powers give her a transcendence.
After the alliance with the Borg, Voyager is filled with Borg technology, and Seven of Nine, cut off from the Collective, begins to reject her implants. The Doctor removes most of them while Kes uses her telepathy to stop a seizure. Seven demands to return to the Borg and tries to send them a signal, but Kes stops her. In the brig Janeway tells her that she was once a human girl named Annika Hansen.
Kes's mental powers grow too strong to control, threatening her own body and the ship, and she decides to leave Voyager. Before she goes, she uses her power to push the ship beyond Borg space and ten years nearer home. Seven takes on a human appearance and stays aboard. The fourth-season episode marks Kes's departure from the regular cast and the start of Seven's long story of learning to be an individual.