Yukoy Debber was an engineering officer on the USS Majestic. He helped Chief Engineer Helfner Berinski get to the spy on the ship along with Feril Salder.
He attacked the spy after the spy fired at Berinski, but was knocked unconscious a few seconds later after the spy hit a console. A few minutes later, he regained consciousness, and restored power to the Majestic's bridge, along with Feril. (Star Trek: Mirror Wars)