Heng-Su was a Chinese scientist sent by General Shi-Hao of the People's Liberation Army to collect the second phase of the Syphon Filter virus in the Agency Bio-Labs in New York City. Through a prearranged deal, the Consortium would supply the virus to Shi-Hao for his rebellion in the Hielongjiang province, which would create a war in Russia and other areas. The Agency had to hurry its production of the virus after delays from retrieving Jonathan Phagan's infected plasma. The Agency was also unable to retrieve Lian Xing's infected plasma, causing further delays to the virus production.
When Heng-Su arrived, Dr. Elsa Weissinger stalled him until everything was ready for a transfer. He was murdered by Gabe Logan, who had been a prisoner in the facility, while Logan was pursuing Weissinger and Lian Xing's vaccine.
Heng-Su's death apparently had an impact on Shi-Hao and his rebellion. His death caused Shi-Hao to enlist the help of the Japanese Red Army (JRA) and use them to retrieve the virus from the Agency. However, Gabriel Logan eliminated Shi-Hao and his JRA underlings, putting an end to his rebellion.