Season 2
By the second season, Deep Space Nine had successfully developed its own identity. Its underlying plot and characters were well defined as the season concentrated heavily on developing its rich set of supporting characters, including Vedek Bareil, Winn Adami, Elim Garak, Gul Dukat, Rom, and Nog.
Bajoran politics and the impact of the Cardassian Occupation are explored deeply. The introduction of The Maquis – a rebel group living in or near the demilitarized zone – lays groundwork for the next Trek spinoff (Voyager). The first mirror universe episode since The Original Series debuts, which will be revisited several times throughout DS9’s run.
Most importantly, Season 2 introduces The Dominium, through subtle hints that lead up to the season finale cliffhanger. The Dominion will ultimately take center stage in driving DS9’s momentum.