Captain Atom appears in the Injustice: Gods Among Comic as a member of Batman's Insurgency.
Nathaniel Christopher Adam had been framed for a crime and sentenced to death under the watch of Col. Wade Eiling in 1968. As an alternative to execution, he was to participate in a military experiment with little chance of survival, in exchange for a pardon. The experiment involved testing the hull of a crashed alien ship's durability by exploding a nuclear bomb under it. Adam survived as the metal melted into his body and the excess energy threw him forward in time nearly twenty years. Blackmailed by Eiling, Adam was given the codename Captain Atom and forced to become a superhero under the U.S. government's command.
Captain Atom is one of the many heroes having been summoned by Batman and Catwoman to join them against Superman's growing Regime. As the summoned heroes sit at a table, Batman asks if they understand why he called them and it is Captain Atom who replies, "Of course. What's our plan of attack?"
Captain Atom snatches a world leader out of Hawkgirl's hands on Batman's command, allowing Black Lightning and Huntress to knock her out. His presence is later noted by the Justice League, which causes them to suspect the U.S. Government's interference, but soon they realize Batman has formed a team to counter them.
Captain Atom is among Batman's gathered Insurgents as the Dark Knight explains the Parademons plan of attack, but remains silent throughout Bruce's explanation. Black Canary mentions that Captain Atom is more than capable of protecting a single city on his own when she suggests they work with the League and Superman.
Captain Atom is present among the gathered Insurgents who learn Bruce Wayne is Batman. When the Superman cultists invade Crime Alley, Captain Atom is sent ahead of the rest to contain them, and is soon joined by the rest of the team before being forced to leave by Wonder Woman and Superman.
Captain Atom is among the gathered Insurgents in one of Batman's many hideouts, watching Black Lightning argue with Batman over Shiera's kidnapping and subsequent replacement with Martian Manhunter. Atom tells Batman that he should have informed them of J'onn being part of their team but learns of Manhunter's death at Superman's hands. After this, Batman tells them of their mission to Superman's Fortress of Solitude to steal the completed nanotech super-soldier pills and brings Captain Atom along in case Superman shows.
The team (consisting of Batman, Catwoman, Black Canary, Atom and Green Arrow who refused to let Dinah go alone) head for the North Pole via a teleporter and Batman has Atom carry Catwoman ahead so she can unlock the Fortress's front door. Catwoman succeeds and Atom opens the massive door before waiting outside on Batman's orders in case Superman arrives.
Unfortunately, Batman didn't plan on Superman's parents being inside the Fortress and his distraction fails to keep Superman occupied long enough and the enraged Man of Steel arrives moments later, grabbing Atom by his neck as he confronts Batman's team.
Captain Atom waits as Superman's parents plead with their son to release him. When Superman fails to respond, Atom tells him, "Okay. I gave you a chance to do the right thing." before blasting the Man of Steel with a nuclear burst that sends him flying into the upper section of the Fortress's entrance, collapsing it.
Captain Atom and Superman take their battle to the icy fields outside the Fortress, with Atom musing on all the different ways he can attack him before explaining how his powers work. After Superman sends him flying back with a sudden punch, Captain Atom explains the reason that whenever they encounter someone else 'like them', all they do is punch each other, with Atom landing a powerful blow across Superman's jaw as he gives the reason: "Because it feels good."
With Superman brought to his knees, Atom explains to him that the Pentagon thinks he can kill him. Atom then explains to Superman why he has never tried before: "Because I serve. Because I fight for my country, not for myself. Because I haven't been ordered to." Knowing that he is not bigger than his country, Atom draws his hand back, gathering more power into his palm as he tells Superman, "Orders have changed."
Before he can deliver the coup de grace, Wonder Woman suddenly appears and strikes Captain Atom across the neck with her sword, breaching his containment suit. Cursing her stupidity, Atom calmly pushes her sword down and explains he cannot contain all his power and now he has a choice to make: To stand there and let it all out in an explosion that would destroy the entire North Pole and everyone currently on it. "Or I can do what's right." Atom says.
Looking down on Superman, Atom asks if he remembers when he thought of anyone other than himself. Telling Superman that he has orders to take him out if the opportunity presents itself, Atom tells the Man of Steel, "I guess this is my last opportunity." Superman attempts to crush Atom's wrist but Atom simply tells him "You can't hurt me. I'm already dead." Flying into the sky with Superman in tow, Atom declares, "And I'm taking you with me."
Flying into the upper atmosphere, Superman struggles against him but Atom calmly and adamantly refuses to let go, with Wonder Woman in close pursuit. His leaking power reaches critical mass and Captain Atom dies in a massive nuclear explosion that destroys several nearby satellites and badly injures Wonder Woman but fails to kill Superman.
Powers and Abilities
Captain Atom is a living nuclear reactor contained in a body suit composed of alien alloy. His vast nuclear energy gives him super strength sufficient to fight Superman on an even field and even defeat the Man of Steel. As stated by Black Canary, he is powerful enough to defend an entire city from an invasion of Parademons by himself. Atom can fly at super sonic speeds well ahead of any ground vehicles and is durable enough to survive several blows from Superman, but is vulnerable to magical weapons such as Wonder Woman's sword.
Captain Atom's entire body is covered in an alien silver alloy like material to contain his vast nuclear power. The suit possesses a red nuclear symbol on his chest, with red lines running up from his back and over his shoulders, with his arms and legs also red, resembling gloves and boots.