When Nicole de Boer replaced Terry Farrell as Star Trek: Deep Space Nine's resident Trill host to the Dax symbiont, she actually solved a problem that had gone unaddressed in the show. Farrell's Lt. Commander Jadzia Dax was one of the most beloved characters on DS9. Jadzia was friends with Quark (Armin Shimerman), was Captain Benjamin Sisko's (Avery Brooks) closest friend, and shared a romance with Lt. Commander Worf (Michael Dorn). When Jadzia Dax died a sudden, senseless, and violent death at the end of DS9 season 6, her replacement with Nicole de Boer's Ezri Dax was controversial.
Lt. Ezri Dax was a success on Star Trek: Deep Space Nine. Whereas Jadzia Dax is the station's Science Officer, Ezri is a counselor. As a therapist, Ezri is a lot more in touch with her emotions and the emotions of others than Jadzia. So, while Jadzia showed what it means to live with and honor the legacy of a Trill symbiont, Ezri revealed more of the personal consequences of having your personality fundamentally changed by the memories of nine lifetimes' worth of experiences.
Star Trek: Deep Space Nine Revealed More Of Ezri's Backstory Than Jadzia Dax
Ezri Was A Person Before She Was A Joined Trill
Star Trek: Deep Space Nine season 7 explained who Ezri was, above and beyond a host to the Dax symbiote. During her six seasons on the show, DS9 never revealed what Jadzia Dax's last name was before she joined with Dax. But Ezri's identity as Ezri Tigan is a part of her from the very beginning. Ezri has a mother and a brother who appear on the show, and it is clear that she had a life before joining with the Dax symbiont.
One reason for this is that Ezri Tigan was only joined with Dax because of the medical emergency caused during the transport of the Dax symbiont back to Trill. As the only Trill aboard, Ezri had to host Dax to keep the symbiont alive. In Ezri's own words:
"I laid down on that operating table one person and I woke up a completely different person. Well, I should say eight different people. I was not prepared for this at all."
What Ezri's history reveals is that there is a kind of horror to being a joined Trill. Everything that Ezri was before was rewritten by Dax, and that is a frankly terrifying premise. What Ezri Dax confirmed is that there is a lot to explore about the psychology of joining as a Trill, and it is a little weird that DS9 never took the time to delve into Jadzia's past in the same way.
DS9 Was More Interested In Previous Dax Hosts Than Who Jadzia Was
It Never Mattered Who Jadzia Was Without Dax
Star Trek: Deep Space Nine was ultimately more interested in exploring the previous hosts for the Dax symbiont than exploring who Jadzia was as a person. Early on, a lot of Jadzia Dax's core interests — from the Ferengi to the Klingons to Captain Sisko himself — could be holdovers from Curzon Dax (Frank Owen Smith). Indeed, in the DS9 season 2 episode, "Invasive Procedures," the Dax symbiont is kidnapped, leaving Jadzia alone for the only time in all of DS9, and she appears as only a shell of her normal self.
By the time Lt. Commanders Jadzia Dax and Worf fall in love, there is no doubt that Jadzia Dax is a full and unique individual.
Star Trek: Deep Space Nine's early exploration of Jadzia Dax's character is more focused on the past lives of the symbiont than the personality of Jadzia herself. Luckily, this changed in later DS9 seasons, as Jadzia's character grew more and more developed. By the time Lt. Commanders Jadzia Dax and Worf fall in love, there is no doubt that Jadzia Dax is a full and unique individual. Nevertheless, little is known about Jadzia's past, and Star Trek: Deep Space Nine was ultimately more interested in her present.
