Masters served basic training with Mitchell Crota, where they first met. (Ask the Characters) He served with Cobalt Squad for all important missions from February to October 2009. (Darwin's Soldiers, Survival of the Fittest)
Masters attempted to save Sharon Redfield's life at Schutzhund but was unsuccessful. He was unsure of his ability to lead Cobalt Squad after Slavik died at Texas Base, but he proved to be up to the task. He survived the events of the Dragonstorm incident and no members of Cobalt Squad died under his command. (Disruptive Selection)
As Crota was stated to be the last surviving member of Cobalt Squad by 2039, Masters must have died some time before then. (Disruptive Selection)
- In the discussion thread, Serris posted further information on Masters's life between the main events of Disruptive Selection and the epilogue thirty years later:
"He was honorably discharged and served as a military consultant for films, TV shows and other entertainment. Unfortunately, his habit of smoking a pack a day for the past thirty years caught up with him. He was diagnosed with lung cancer. Removal of the cancerous part of his lung, radiation and chemotherapy helped. But the cancer returned five years later. Seeing as Snakes only have one lung, the doctors dared not do more surgery. Radiation and chemotherapy helped somewhat but it was for naught. He was sent home with his family to live his remaining time in peace. After spending months in near constant pain, he pleaded for an intentional overdose of sedatives. After the staff and family refuse his request, he seeks to commit suicide with his old service pistol. After finding out they removed his guns, he crawls into the freezer to end his life."