Star Trek: Discovery's Adira & Admiral Tal Trill Twist Explained
Warning: SPOILERS for Star Trek: Discovery season 3, episode 3, "People of Earth".
Star Trek: Discovery's new character, Adira (Blu del Barrio), harbored a secret that's revealed at the end of season 3, episode 3: Even though she is human, Adira is also the host of a Trill symbiont. Adira is a historic addition to Star Trek as Blu del Barrio is the first non-binary actor to join the franchise - although when Adira is introduced, Captain Saru (Doug Jones) refers to the new addition to the U.S.S. Discovery's crew as "she". However, there is clearly much more to Adira than meets the eye and she appears to be the source of even further mysteries.
In episode 3 of Star Trek: Discovery season 3, "People of Earth", Commander Michael Burnham (Sonequa Martin-Green) is reunited with the Discovery after arriving in the 32nd century one year before her crew. Joining forces with her new friend, Cleveland "Book" Booker (David Ajala), Michael became a courier and spent that year searching the galaxy for answers to what caused the Burn, the calamity that led to the collapse of the United Federation of Planets. Burnham updated Discovery's senior staff about what she's learned, including her finding a 12-year-old message from a Starfleet Admiral named Senna Tal, who urged other "true believers" in the Federation to find him. The Discovery's course was clear and they jumped to Earth in order to check in with Starfleet to hopefully find some answers.
After being greeted with hostility from the United Earth Defense Force, the Discovery was boarded and inspected at gunpoint. Although she admitted she was only 16, Adira was one of the inspectors and she immediately drew the suspicion of Lt. Paul Stamets (Anthony Rapp) and Ensign Sylvia Tilly (Mary Wiseman). The Starfleet engineers quickly learned Adira that sabotaged her own team's inspection but, when confronted by Stamets, Adira revealed that she wished to remain aboard Discovery to help them. But the biggest bombshell of all was that Adira claimed that she was Admiral Senna Tal because the Tal symbiont was bonded to her. Yet, this creates even more questions about this mysterious youth.
The United Earth Defense Force's Captain Ndoye (Phumzile Sitole) told Burnham and Saru that Admiral Senna Tal died on a transport two years prior, which would mean it happened in 3187 when Adira was 14. Yet Adira claims that the Tal symbiont was somehow bonded to her, but it hasn't been revealed why or how this is even possible. Further, because Adira is human, she can't access the Tal symbiont's memories the way a Trill host could, so she can't answer the questions the crew of the Discovery needs to know about Admiral Tal and the information he possesses about the Burn, Starfleet, and the Federation.
Trills have been well-explored on Star Trek: Deep Space Nine; Lt. Commander Jadzia Dax (Terry Farrell) and her successor Lt. Ezri Dax (Nicole de Boer) have also introduced many of the previous hosts of the Dax symbiont like Curzon Dax (Frank Owen Smith), who was the Ambassador to the Klingon Empire and mentor of Captain Benjamin Sisko (Avery Brooks). In fact, Ezri wasn't supposed to be the host of the Dax symbiont but an accident aboard a starship required her to bond with the symbiont or else Dax would have died. It's possible, then, that the same thing happened to Adira if she was on the same transport as Admiral Tal and an accident occurred that necessitated the Tal symbiont bonding to her.
It's still baffling how the human Adira could be the host of a Trill symbiont; however, Star Trek: Discovery season 3 is set over 800 years after Star Trek: Deep Space Nine so some things could have biologically changed between both the human and Trill races for this miracle to take place. But it was also announced that another new character, Grey, would be joining the series. Grey is a Trill played by Ian Alexander, who is Star Trek's first transgender actor. Adira and Grey are supposed to have a close relationship so the answers to Adira's mystery must be tied to Grey and will be revealed later on in Star Trek: Discovery season 3.