In the mirror universe, Zarale was a Cardassian gul who served in the Klingon-Cardassian Alliance during the 24th century. From 2358 until at least 2375, he was the commander of the mining colony Korvat.
In 2361, a Terran slave named Keiko Ishikawa had her lover, the Cardassian overseer Glinn Broca, arrange for her to have a meeting with Zarale, at which she informed him of the plot to kill the Klingon slave overseer Kozak. After the relevant slaves were taken into custody, Keiko suggested to Zarale that he spare their lives as further deaths in Kozak's section would only result in less efficiency for the mine. Zarale followed her advice.
In reality, Keiko was an operative of Memory Omega who had manipulated Broca into arranging the meeting so that she could find her way into Zarale's bed. Over the course of the next four years, she gradually gained his trust and was able to subtly manipulate him, as she had done with her previous lover Broca. By 2365, Kozak had become a drunkard who was no longer able to perform his duty to the required degree. Given that he had been found derelict, he was relieved of his position and executed by two Cardassian guards at Zarale's orders.
Keiko succeeded Kozak as overseer and served in that position until she and 98 other slaves escaped to Terok Nor, the headquarters of the Terran Rebellion, in 2375. However, she regretted not killing Zarale in his sleep when she had the opportunity. (DS9 - Mirror Universe short story: "A Terrible Beauty")