Tseng was a soldier of the Moebius Foundation who served at Space Station Prometheus. During the Flashpoint Conflict, Tseng was ordered by Emil Narud to apprehend Jim Raynor and Valerian Mengsk. However, Naurd also released the facility's hybrid to deal with them. Tseng and their comrades, (Vrain, Osgood, Warren, and Mitchell) were attacked by the hybrid and immediately killed.