She was formally known as Ezri Tigan, before being joined with the Trill Dax. Being the ninth host, she served as a Councillor on Deep Space Nine, after Jadzia died. Being paired up with the with the Dax symbiont on the Starship Destiny because she was the only unjoined Trill.
She was then brought to the Trill homeworld to meet with the Symbionce Commission Evaluation Board, who instructed her to deal with her new memories, but they were unable to help. Her friends and family were having difficulty dealing with the change as well. Her confusion with her identity caused her to take a leave of absence. She traveled to Earth seeking council from Benjamin Sisko, where she uncovered the Orb of the Emissary, restoring the Prophets to the Celestial Temple. She then took commission on Deep Space Nine for the remainder of the Dominion War.