The Flash (Injustice)

"This isn't what we signed up for. I let myself believe we were making things better. But we're not."

- The Flash, after Superman crossed his Moral Event Horizon

The Flash is a playable character in Injustice: Gods Among Us. He is classified as a Gadget user. He relies entirely upon his speed, literally running circles around slower opponents.

Biography
After an electrical accident at his lab, scientist Barry Allen was left with the ability to move, think and react at super speeds. A member of the Justice League, the Flash uses his super speed to fight crime.

The Flash joined Superman’s One Earth government out of fear. He might have believed in its ideology at the beginning, but lately serious doubts have begun to creep in.

Events in Injustice
The Flash is first seen as an agent of Superman's Regime, along with Shazam, supervising the treaty with Aquaman about surrendering Atlantis to the Regime's rule. What he didn't know was the Aquaman they're meeting was instead Aquaman from the main universe, enraged with the basis of the treaty and declaring that Atlantis should not surrender. Flash and Shazam tried subduing Aquaman, but were defeated and even when the Regime's Aquaman came to attack his other, more righteous self, he was defeated.

Flash is later seen in the Watchtower, expressing his doubts about serving the Regime with Shazam, but was convinced to stay by Shazam. He was later attacked by Deathstroke and knocked out as Deathstroke planted the bomb in the Watchtower. Flash, however, survived as Cyborg teleported everyone to safety before the tower exploded.

After the attack on Stryker Island, Superman announced that he would destroy both Gotham and Metropolis to set an example to the people, and cold bloodedly killed the protesting Shazam. At that point, Flash finally realized that the Regime isn't doing the right thing and promptly defected, going past Yellow Lantern and Solomon Grundy and rendezvoused with the Insurgency, surprised to see Green Arrow as the Green Arrow he knew was killed by Superman for voicing an opposition against the Regime.

After a brief battle due to misunderstanding, the Insurgency, filled with heroes from the main universe, welcomed Flash to explain his purpose. Flash revealed Superman's plan to destroy Metropolis and Gotham, but soon the Regime attacks the hideout and forced the heroes to move out and defend the first city attacked: Metropolis. However, the battle eventually ended as the main universe Superman was summoned and defeated the Regime's Superman.

Despite helping the Insurgency bringing peace back to the world, Flash surrendered himself to the police to atone for his sins of serving the Regime, a decision he's content with. Before he's carted off, he gave a last look to Green Arrow, giving a smile and his acknowledgement that he knew what to do.