In the episode "Battle Lines", Opaka - who had never left Bajor in her life - left her world for the first and last time. She visited Deep Space 9 and requested that Commander Sisko allow her to see the Bajoran Wormhole, which only became visible when traversed. Sisko, Major Kira and Dr. Bashir took the Kai aboard the runabout Yhangzee Kiang and took her through the wormhole, but shortly afterward they recieved a signal coming from a nearby planet. When they investigated the planet, the runabout was shot down by a satellite network surrounding the planet. Sisko, Bashir and Kira survived the crash but Opaka was killed.
However, the satellites had saturated the planet's atmosphere with artificial microbes that kept its inhabitants alive. Having died within the planet's ecosystem, Opaka was ressurrected. It was later discovered that the planet's inhabitants - the Ennis and the Nol-Ennis - were prisoners on the planet, sent by their leaders to endure everlasting punishment for their war crimes by never being able to die, and so their war continued with both sides constantly battling and killing each other over and over again. Sisko and his crew were able to contact DS9 and arrange a rescue, hoping to also end the torture of the Ennis and Nol by taking them off the prison planet and resettling them on different worlds. However, Dr. Bashir discovered that the microbes would stop functioning if they were removed from the planet's ecosystem, meaning that any Nol or Ennis - who had all died several times - who left the planet would immediately die, this time permanently. For the Nol and Ennis, a final death would be welcome, but Opaka would also die if she left. The Kai decided that she would remain on the planet and try to teach the Nol and Ennis peace, and so when Sisko and his crew were rescued, they left Opaka behind, never to see her again.
- Opaka's given name is "Sulan", making her full name Opaka Sulan (Bajoran family names always come before their given names). Her given name is never mentioned on-screen but is mentioned in the DS9 novel, Unity.