The mirror universe counterpart of Ezri Dax, an unjoined Trill mercenary who works for the Alliance in 2375 before throwing in her lot with the Terran rebels.
Ezri Tigan appears in the Deep Space Nine episode The Emperor's New Cloak. In the mirror universe she never received the Dax symbiont. She is a hired gun, close to Intendant Kira, and she crosses into the prime universe to make sure Quark and Rom deliver a stolen Klingon cloaking device as ransom for Grand Nagus Zek.
Her partner is the mirror Brunt, a gentle Ferengi who is devoted to her. When the Intendant murders him, Ezri's loyalty to the Alliance breaks.
She helps Quark, Rom and Zek escape from Regent Worf's flagship, and the sabotaged cloak leaves the ship helpless before the rebel Defiant. She is last seen leaving with the rebels, in the company of the mirror Leeta.