Star Trek: Discovery is set to visit the Trill homeworld at some point over the course of season 3; what exactly are the Trill, and why are they significant to the Star Trek universe? With season 1 of Star Trek: Picard just around the corner, and season 3 of Discovery in the near future as well, it's an exciting time to be a Star Trek fan. However, with so much new content on the way and so much existing lore to catch up on, it can sometimes be easy to miss out on crucial elements of the large extended universe that may become important in shows like Discovery.
Discovery ended on a massive cliffhanger when it literally hurled its entire cast into an unknown future, virtually wiping the slate clean for any and all races and species to make an appearance — whether they're new to the show or they have their roots in Star Trek: The Original Series. Key species from The Next Generation and Deep Space Nine, like the Cardassians and the Ferengi, have already been confirmed to be making appearances on Discovery, but there's another fan-favorite species who will be returning to the small screen: the Trill.
While they have yet to make a significant appearance so far in Discovery, showrunner Alex Kurtzman has confirmed that season 3 will take audiences to the Trill homeworld. Coupled with stills of Michael Burnham standing by what looks to be the Trill symbiont pools (below), all signs seem to point to the Trill playing a significant role in season 3.
The Trill Species Explained
The Trill is a humanoid alien species native to the planet Trill. As a species on their own, the Trill are fairly unremarkable, apart from one, key quality: the symbionts. The Trill have no significant conflicts with neighboring planets or empires, and their society is a relatively secluded and peaceful one. Their most obvious outward distinction is their trademark spots, which run from the forehead to the toes on both sides of a Trill's body. Inside, however, the Trill have the unique ability of hosting another species, known as the symbiont.
Not all Trill host a symbiont; like many other Star Trek aliens that appear human, most Trill are humanoids with few aesthetic differences from other similar alien species. A small number of the species participates in a unique and rare process known as "joining." Thanks to a neurotransmitter in their physiology called isoboramine, some Trill can be surgically "joined" with a creature known as a symbiont. Symbionts have a worm-like appearance, and are small enough to reside in a Trill's abdomen. The number of Trill greatly outnumbers the number of symbionts, however, so the process of deciding which Trill will receive the honor to be joined with a symbiont is a long and rigorous one.
Once a Trill has been deemed fit to host a symbiont, they are joined together in an irreversible process. Once joined, the Trill's and the symbiont's minds are melded, combining both of their life experiences and memories to create one being. The two will live as one until the Trill is no longer healthy enough to host the symbiont, at which point the symbiont will be transferred into a different Trill, the old host dies, and the cycle begins anew.
As previously mentioned, the chance to host a symbiont is seen as a great honor on the Trill homeworld, and there is stiff competition between unjoined Trill to see who will end up with a symbiont. Additionally, the joining of a Trill and symbiont can be a volatile one — if they are separated after the initial joining period has elapsed, both will die within hours unless new respective symbionts and hosts are found to replace what was lost.
Trill History in Star Trek
Surprisingly, knowledge of Trill customs (especially the Trill joining process) was incredibly limited in the Federation, even as late as the 24th century. As such, there have only been a few Trill in the Star Trek universe with a significant onscreen presence. The first Trill introduced in-depth was during The Next Generation season 4, episode 23, "The Host". The episode sees Doctor Crusher begin a romance with a joined Trill named Oran, whose symbiont is temporarily transferred to Commander Riker after its host is killed in an accident.
In the episode, the Trill are depicted as having forehead ridges and a noise piece as opposed to the spots traditionally associated with the species. The Trill's signature spots didn't occur until Paramount executives rejected early Deep Space Nine makeup tests because the forehead pieces allegedly obscured actress Terry Farrell's beauty. Speaking of Farrell, it was through her character, Jadzia Dax, that the Trill became more than a one-off species and solidified themselves as a mainstay of the Trek universe.
Jadzia was a Trill joined with the symbiont Dax, and she served as DS9's resident science officer. Dax's previous host, Curzon, was close friends with Captain Benjamin Sisko, and over the course of the series, Jadzia fell in love with (and married) Worf. However, in a tragic turn of events, she was killed, and the symbiont was transferred to Ezri, becoming Ezri Dax. Ezri took a position as the station's counsellor and eventually entered into a romantic relationship with Doctor Bashir, the station's CMO.
How The Trill Fit Into Star Trek Discovery Season 3
Through Jadzia, Ezri, and the Dax symbiont, Trek audience got a much deeper look at the history and culture of the Trill, but it's unclear as to how much of that culture will be featured in season 3 of Discovery, especially considering that when the events of Discovery begin, the Trill have had very little interaction with Starfleet. Given that Discovery made a 900-year jump through the future, however, it's possible that Michael and her crewmates could run into the Trill during their time in the future, however long it ends up being.
Given that Discovery's Michael Burnham was pictured at the Trill pools, which are unique to the Trill homeworld, it's entirely possible that Star Trek: Discovery will be making a visit to the Trill planet this season, whether it's in the past or the present. It's also entirely possible that the crew of the Discovery could run into a version of Dax — either an unknown host to the symbiont in the future or one of Dax's previous hosts (however, it's unclear as to exactly who was hosting the Dax symbiont around 2255; it could be either Emony or Tobin). No matter how audiences meet the Trill this season, though, it's bound to be a welcome return for a species that haven't been seen since Deep Space Nine.