Firestorm, the Nuclear Man, is the fusion of high school student Ronnie Raymond and Professor Martin Stein. The two were caught within the area of a nuclear accident that fused the two, making them into Firestorm. Ronnie is the body of Firestorm while Martin's mind coexists in Ronnie's head. This is important, as Stein can calculate the complex matter manipulation that is one of Firestorm's main abilities. Firestorm has spent some time as part of the Justice League of America too. Another high schooler, Jason Rasch, was both the body and the mind of Firestorm at different points as well, until the recent reunion of Ronnie and Martin.
That matter manipulation, as well as his powerful energy blasts, also make Firestorm easily one of the most powerful superheroes in DC Comics. He has done some insane things with those powers over the years, and these are his most insane displays, ranked.
10 The Bunny Suit
One of the most entertaining uses of Firestorm's power took place post-Flashpoint when Jason and Ronnie began combining into a more traditional Firestorm.
While stopping a hi-tech heist being carried out by some low-level mercenaries, Firestorm manifested a pink bunny suit around the villain Skull-Crusher, which left the rogue quite unhappy--if somewhat less intimidating.
9 Fury Of The Firestorm
The new gimmick of Firestorm in his early days in the New 52 DC Universe was that Ronnie and Jason were separate Firestorms. Ronnie could conjure the energy blasts, and Jason could manipulate matter. When the two came together, they created Fury.
This form was even more powerful than the Firestorm of old, able to manipulate even organic matter and releasing massive energy blasts. It was also a mindless rampaging beast akin to the Incredible Hulk. Eventually, Ronnie and Jason were cured of Fury and became the Firestorm of old.
8 Capturing Three Justice Leagues
When the Crime Syndicate arrived on our Earth at the end of the Trinity War storyline, a new Deathstorm arrived with the Syndicate. This one was able to absorb all three Justice League teams into its Firestorm Matrix, the energy nexus which allows for the Firestorm fusion and holds together the minds and bodies of the two people who make up Firestorm.
Batman and Catwoman were able to escape this calamity, and the rest were later freed by the team of villains put together by Lex Luthor.
7 Curing Ronnie's Leukemia
At one point, Ronnie Raymond was fused with a Russian analog to Firestorm called Pozhar, and Martin Stein became a fire elemental version of Firestorm and traveled into space. Ronnie and Pozhar were Firestorm for some time, but Ronnie later came down with Leukemia.
His health faded, but, before Ronnie passed on, Martin Stein returned to Earth and, with some help from Captain Atom of the Justice League, cured Ronnie's leukemia. Ronnie became Firestorm again not long afterward.
6 Turning Things Into Salt
Firestorm's matter manipulation isn't supposed to affect living beings, but there have been some exceptions. When Ronnie was resurrected as the Black Lantern Deathstorm, he absorbed Jason into his Firestorm Matrix.
This separated Jason from his girlfriend and Firestorm partner, Gehenna. Deathstorm turned Gehenna into salt as he ripped out her heart. Later, after Ronnie was resurrected by the White Lantern Entity, Jason still held a grudge against Ronnie over Deathstorm's actions. At one point, they entered a heated argument and fused into Firestorm on accident, turning everything around them into salt.
5 Surviving A Nuclear Bomb
When Firestorm first fought Pozhar, it was over the former's crusade to stop nuclear proliferation around the world.
Firestorm and Pozhar fought one another in the Nevada desert, and a nuclear bomb was dropped on them both. They both survived the experience, fusing into a new Firestorm made up of Ronnie and Pozhar.
4 Absorbing A Nuclear Meltdown
Firestorm has also proven to be able to stop a nuclear meltdown. Hudson Nuclear Power Plant, Martin Stein's grand experiment in safe nuclear power, was sabotaged by anti-nuclear extremists.
The ensuing explosion created Firestorm by fusing Ronnie Raymond and Martin Stein. Later, they returned to absorb the excess radiation from the reactor core to make sure another meltdown never happened.
3 Turning A Crowd Of People Into Glass
In the recent Doomsday Clock story, Firestorm found himself surrounded by protestors in Russia. In a panic, Firestorm accidentally turned the crowd of protesters into glass.
Ronnie tried to turn them back but found himself unable to do so. He fled the scene with a glass child after some of the protesters began shattering.
2 Closing The Rift Caused By Alexander Luthor
Alexander Luthor and Superboy-Prime began trying to construct the "perfect Earth" during Infinite Crisis, and Luthor opened a multiversal rift at the center of the DC Universe to accomplish this task.
Jason Rusch and Martin Stein, then fused as Firestorm, were able to stop Alexander Luthor and seal the rift he created in our universe.
1 Detonating Captain Atom Across Time And Space
Not long ago, the U.S. government was after Firestorm. It was the Ronnie and Jason fusion at the time, and the two were being chased by none other than Captain Atom, the man made of pure energy (not working on behalf of the Justice League at this point).
Firestorm and Captain Atom fought, and, at one point, charged at one another. The collision detonated Captain Atom, launching shards of his containment suit across time and space. Nathaniel Adams himself, somehow restored to his human body was sent to the far future, where he was found by Legion of Super-Heroes. None of this was really explained or resolved, but it was a cool moment nonetheless.