Firestorm — dc

Firestorm the Nuclear Man is a legacy codename given to multiple individuals across the DC Universe. Firestorm is a nuclear-powered super-hero with the ability to transmute elements. The Firestorm Matrix is a composite of multiple people bonded together. Individuals connected to the Firestorm Matrix are considered members of the Parliament of Flames.

The original Firestorm was a composite comprised of high school student Ronnie Raymond controlling the body, with nuclear physicist Professor Martin Stein giving direction as an additional consciousness.
Mikhail Arkadin became a later Firestorm, merged with Ronnie Raymond.
At one point, Martin Stein took control of the Firestorm Matrix solely and assumed the identity of Firestorm without being merged with anyone else.
Lorraine Reilly was also part of the Firestorm Matrix for a time, as an independent user.
Jason Rusch took over the identity after the death of Raymond during Identity Crisis and went through several composite partners, including his close friend Mick Wong, and his girlfriend Gehenna.