The spray hissed, as he finished painting over the Wayne Municipal Corporation sign. A smile as wide as a man was tall, full of hideously misshapen teeth. Purple covering up everything else. He finished his art with one of his slogans.
According to his grandmother, he had his grandfather's gaunt frame. It made the garish suit, dark purple with pinstripe, look good on him. He wore white magicians gloves, black loafers, and a red cloak hung from his shoulders. A red hood capped off his costume.
Things had really got out of hand when it killed the Alien's son. Before that it had just been a sad local story. Killing the vigilante who'd worn it, squishing him like an insect. Then it massacred active criminals. Criminals like his older sisters. They'd been gangsters, might have even deserved serious jail time, but no one deserved to have there heads twisted off like bottle-caps.
Hood wore a suit of medical grade plastic under his clothes to keep his forensics to a minimum and a skin-tight power suit under that. It wasn't entirely unlike the suit the tyrant had been spawned from. It had originated on the Twin Worlds, though his had been liberated from Inter-Gang terrorists and not received as a gift from the original extraterrestrials.
A pair of guns hung from his hips, and his belt was full of gadgets. This was still Gotham, after all.
When the half-kryptonian came to Gotham to stop it, it shoved a green crystal capped claw into his eye, moving faster then the eye could follow. The great league descend on the city, to bring the machine to some kind of justice, but it had evolved. It had linked with the vigilante's super-computers and assimilated his machines. It showed no hesitation or doubt. It thought just like the Bat, like the original, but had none of his morals. In weeks it had done what two lifetimes of costumed psychopaths had failed at.
Hood could have just mourned his sisters, gotten over it, but it got worse. He'd never met his parents. His grandmother and her wife had raised him. They had both had a bad past, but had managed to recover and find some kind of reformation. His grandmother had resumed her work as a psycho-therapist and his step-grandmother had returned to bio-chemistry.
It had been a rough world outside there front door, but a quiet one inside. Then the tyrant decided to close up loose ends. It came for them, smeared the walls of there cozy home with viscera. 
Hood fled the country, went to Europe. Meet his master there, the scar-faced man. Master claimed he'd gotten that scar from the swipe of a saber-toothed cat, but his constant sneer made everything he said sound like a lie.
Hood learned to fight, learned to think like a proper villain. He took up chemistry like his grandfather, found he had talent for it.
As the whine of the local enforcement drones filled the air, Red Hood fled in to the shadows, laughing like a loon at a joke only he could understand.
Now he was back in the Bad Apple, Arkham City. He huffed self-mixed combat gases everyday, experimented on himself, improving his reflexes, speeding up his thought processes. The stimulants made him paranoid, so he spent most of his time alone, talking to himself, laughing. He pushed the edge of what his heart could stand to out-think The Machine.
Well, that's how it goes. Whatever doesn't kill you makes you stranger.