Star Trek: 10 Underrated Villains
2. Kai Winn
As a general rule, the Bajorans were guided through life by their faith. Their gods were called the Prophets, and they the communicated with the Bajorans through the Orbs. The leader of the Bajorans religion was called the Kai, the first one Benjamin Sisko encountered being Kai Opaka. She was an intelligent, spiritual leader who led her people through much of the Cardassian occupation.
But when Opaka was forced to leave her post, an election was held to decide her successor. The eventual winner was Kai Winn Adami, an ambitious, duplicitous individual who was frequently selfish and more than a little xenophobic. She was also not a fan of Captain Sisko being the Emissary of the Prophets, due to the xenophobia as well as the fact that he was better at his job than her.
While Gul Dukat has generally been regarded as Sisko's primary nemesis, and he certainly was, Winn was a bigger thorn in the side of the Federation. Even when it seemed like Winn was one of the good guys, she was always working her own angle. Winn even sided with the Dukat and the Pah Wraiths in the final battles.