Firestorm, the Nuclear Man, Vol. 3 #35 (2007)

The End Is Here
Orion fights Kalibak as Firestorm tackles the parademons. Kalibak overcomes Orion and takes on Firestorm who battles him for as long as he can before taking him high into the air and causing a nuclear explosion, the only thing that will knock out Kalibak.As the heroes discuss what to do, Darkseid arrives and forcibly pulls Martin Stein out of Firestorm's body. Firestorm merges with his girlfriend, Gehenna, and plans to find both Darkseid and Professor Stein.
Release Date: 2007