Doctor Simon Tsung was an investigator for the International Operations agency related to superpowered beings. He was the creator of the military program that first introduced the Gen-Factor into human subjects.
When he was young Simon Tsung was married and had a wife and a daughter. Both of them died when Sigma arrived to Tsung dimension. Studing the baby, Tsung discovered than the secrets hid in his genetic code hide the geno-factor. However Tsung disagree on how IO and Miles Craven used this discovery.
Tsung asked for help to Admirtal Cray, a friend and man of honer who helped Tsug to hide from IO and to raise Sigma a his own son. Several years later, Tsung, now married again, had become a professor and trained Sigma, aka Ethan McCain, in a virtual reality, preparing him to the arrival of Damocles, something than Tsung unconciously knewn.
Eventually agents of Kaizen Gamorra discovered his refugee and went into capturing him to complete the project of Gamorra, the Omega Factor, who was intended to be a host for the mind of Miles Craven. However, as the sources of the genofactor were the members of Team 7, the project fallen apart.
Tsung and Ethan returned to their home to find htheir family, where all the truth was revealed. However was in that moment when Damocles apeared and abducted the family of Tsung. As Tsung and Sigma followed Damnocles to the moon, in the following battle, the truth was revealed: Dr. and Damocles.were two variants of the same person. After the discovery, Tsung tried to make understand Damocles about his misguided ways, but Damocles resisted. Only the sacrifice of Deathblow saved Tsung and his family.