Star Trek: Deep Space Nine expanded the Star Trek universe significantly when it debuted in 1992. A spinoff of Star Trek: The Next Generation, DS9 introduced a host of new and unusual characters, many of whom were instantly iconic. All of them shined throughout the seven-year run of the show, but some had better seasons than others.
The show's cast expanded greatly as the series went on, with numerous secondary and recurring characters. This made it hard sometimes for the core characters to get the spotlight, but when they did, it was more than memorable. The storytelling of the show was serialized rather than episodic, an aspect far ahead of its time for a Trek series, and it helped make each character grow through the seasons.
Season 1: Major Kira
Major Kira Nerys is a standout throughout the entire series, a complex and nuanced character that in many ways defined how different this show would be from its predecessors. That distinction was instrumental in some of the best episodes from the first season when the show was still finding its feet. "Duet" remains one of the best episodes in the history of Star Trek for how it tackles the difficult relationship between Kira, a victim of the Cardassians, and her abuser, a Cardassian prisoner.
Kira's complicated relationship with her past a Bajoran freedom fighter is also explored in "Progress," where she has to push her own people off of a Bajoran moon. The entire season examines her critical role in the show's many poles of influence, including Starfleet, Bajor, and the Cardassians.
Season 2: Chief O'Brien
"Hard Time," a key second-season episode, shows how different things are for Chief O'Brien than they were on the U.S.S. Enterprise. This showcase for outstanding Irish actor Colm Meaney uses flashbacks and disorienting scenes with O'Brien's crew and family to unravel his PTSD and trauma from being a prisoner. This episode is just one of many that begin to dive into O'Brien as a character after serving in a mostly cameo role on Star Trek: The Next Generation.
O'Brien also shines in other season two episodes, including "Armageddon Game." In this installment, he pairs up with his friend Dr. Julian Bashir to destroy biological weapons, and they're stranded. The isolation adds dimension to the character and his relationship with Bashir, a key aspect of the show.
Season 3: Quark
Quark is part of some of the funniest episodes of Star Trek, with most of them being centered on the Ferengi. "The House Of Quark" is no exception, helping to make the third season a standout for him. Despite the story's shift toward the Dominion and the mystery of the Founders, Quark shines in season three more than ever. His funny exploits, like having to marry a Klingon woman to avoid being killed for the death of another Klingon, helps lift the mood of what is increasingly a gloomy show.
Other standout moments from season three include "Prophet Motive," in which he has to confront the Ferengi leader, played by Wallace Shawn, over changes to the Ferengi way of life. Quark keeps it light but still complicated throughout, as he did in the entire series.
Season 4: Odo
Odo is one of the best crew members in the history of Star Trek for his unwavering loyalty and dedication. That was on full display throughout, but especially in season four, when his complex relationship with The Founders took dramatic turns. In episodes like the season finale, "Broken Link," Odo pays a severe price for siding with the Alpha Quadrant over the Founders, the leaders of the Dominion from the Gamma Quadrant. For his perceived crime, Odo is rendered human and unable to link with his people.
This allows the late actor Rene Auberjonois to really stretch his dramatic wings in the part. Other key episodes from the season do as well, like "Homefront" and "Paradise Lost," where Odo has to face suspicion and persecution as a changeling from a Federation that has gone paranoid over the shapeshifting alien threat.
Season 5: Dr. Bashir
Season five is absolutely key to Dr. Julian Bashir as a character. It's in this season that he and the audience both learn a dark truth about him. "Dr. Bashir, I Presume" reveals that Bashir is the product of genetic experimentation, long outlawed in the Federation thanks to the Eugenics Wars that spawned Khan Noonien Singh. These augmentations contributed to Bashir's intelligence and overall ability, giving him an unfair advantage over others.
He's also at the center of "In Purgatory's Shadow" and "By Inferno's Light," a pair of episodes in which he is captured and placed in a Dominion prison camp. These two episodes stretch Bashir as far as he can go, and he is replaced by a changeling spy who tries to destroy Deep Space Nine and the entire Bajoran solar system.
Season 6: Jadzia Dax
Jadzia Dax was an infinitely compelling character from the beginning of the series, a young Trill woman with a symbiote who had been many other people for centuries prior. Season six might have seen her best moments, though. The season is very memorable for being when Jadzia marries Worf in "You Are Cordially Invited," a happy culmination for one of the best couples in Star Trek. It doesn't end well, though, as Jadzia dies tragically in the season finale, bringing an end to her arc.
Her death is abrupt and painful for the crew and fans, especially at the end of a season that also included "Change Of Heart." In this episode, Jadzia is injured and she implores Worf, her fiancee and colleague, to leave her behind to complete a mission. He doesn't, with disastrous consequences for the war against the Dominion.
Season 7: Captain Sisko
Captain Benjamin Sisko is a major force throughout the entire series, with his hero's journey integral to the entire arc of the show. Season seven is the apex of that journey. A discouraged Sisko, broken by the death of Jadzia and the weight of the war with the Dominion, retreats to his home back on Earth early in the season. But with help from his family and Ezri Dax, he returns to the station and recommits to the war and his destiny as the Voice Of The Prophets, ultimately leaving his corporeal life behind.
Though Sisko may have had better individual episodes in earlier seasons, like the all-time classics "In The Pale Moonlight" or "Far Beyond The Stars," the seventh season and its tremendous climax belong to the hero at the center of the story.