(coexisting on another dimensional plane)
Ezri Tigan was an unjoined Trill mercenary who along with Brunt frequently worked for the Klingon-Cardassian Alliance. Brunt and Ezri shared a strong friendship. Ezri had a sexual relationship with Intendant Kira Nerys, who in 2375 selected Ezri to cross over into another universe on a mission to blackmail Quark and Rom into stealing a Klingon cloaking device and smuggling it into the mirror universe. This mission was successful; however Rom subsequently sabotaged the cloaking device, providing the Terran rebels with an opportunity to force the surrender of Regent Worf. Following Brunt's death at Kira's hands, Ezri chose to betray Kira and helped the Ferengi escape to rebel-occupied Terok Nor, where she joined the Terran Rebellion and was "debriefed" by Leeta. (DS9: "The Emperor's New Cloak")
In the Mirror Universe novel Rise Like Lions, Ezri marries Leeta and becomes first officer and later commander of the Defiant. She also becomes the host to the Dax symbiont after the death of Curzon, who was the last joined Trill in this universe after Spock ordered their extermination.