Chun "Big Dog" Leung was a marine raised on Pridewater. He was aggressive in combat, and kept very good care of his C-14 rifle, "Mayumi". He would not let anyone else touch it. He was also a good poker player.
He served under Arcturus Mengsk in Dominion section. In August 2480, a period when he and the rest of the section were supposed to be on leave, he experienced his first taste of action, forcibly removing Kel-Morian miners from their claim in Turanga Canyon, Leung successfully flanking them alongside Mengsk and fellow section member Dia de Santo.
Leung served under Mengsk over the next five years, serving on worlds such as Parragos and Pho-Rekh while remaining obsessive over Mayumi the entire time. However, Leung was killed in 2485 by an explosion, saving Mengsk's life during the Battle of Noranda Glacier. His last wish was that his commander would keep Mayumi, which Mengsk granted.