Ronnie Raymond, Mikhail Arkadin, and Martin Stein first merged to form Firestorm in Firestorm Annual (DC, 1987 series) #5 ([October] 1987).
Initially, it was believed that Martin Stein had died in the explosion that created the new Firestorm. However, in Firestorm the Nuclear Man (DC, 1987 series) #75 (September 1988), Stein was found alive at the Dry Lake Mental Institution in Nevada, suffering from amnesia. His doctor explained that their "John Doe" would randomly and inexplicably fall into a comatose state. Ronnie and Mikhail realized this occurred whenever they became Firestorm. In issue #86 (June 1989), it was explicitly stated that Martin Stein was part of Firestorm until Svarozhich was added to the matrix.