Leonard McCoy (mirror)

In the mirror universe, Leonard McCoy was a Terran male who served as chief medical officer aboard the ISS in the 2260s.

In 2267, McCoy accompanied Captain to the surface of  to discuss the acquisition of the planet's dilithium deposits for the Empire. When negotiations failed, Kirk and party beamed back up to the ship but an ion storm caused the party to be replaced by the primary universe counterparts. Thankfully, the transport was eventually reversed. 

Following this mission, McCoy and the party were ordered not to reveal any information about the crossover to the crew, yet the majority of the crew seemed to know about it after a few weeks. Following Kirk's assassination, McCoy continued to serve as CMO under Spock, yet he would continue to conspire against Spock along with and  as Spock engineered his rise to the top.

Unfortunately, McCoy finally died in 2269 following a long battle against. (' : '; : "A Burning House")