My Heaven Smile and The Devil Have Mercy

Age: 25
Height: 5'11"
Weight: 180lbs (rough estimate)
Hair Color: Chestnut
Eye Color: Blue-grey
Further detail: His skin is relatively pale though rough and scarred in many places though luckily not on his face, and though sometimes appearing sunken his eyes have a bright and piercing quality. His hair is easily ruffled and nearly always looks windswept or as if he'd just gotten out of bed, his facial hair however is almost non existent and it takes careful observation and the right lighting to notice it. He'd probably be handsome if he didn't look like he hadn't slept in two or three days. His body is lean and fast though by no means weak, as he can lift twice his body weight without much effort.
A pretty nice guy, ya know, if you can get past the homicidal blood-lust.
He wears a a tough leather long coat and keeps blades of a variety of shapes and sizes under it.
John had rather unexceptional childhood up until his adolescence. That is when the voices started. Whispers to kill. To beat, to stab, to rip, to break, to smash, to destroy. They were fairly easy to ignore, until the first time he gave into them in a fit of rage at the tender age of fourteen. After that the voices built up, becoming louder and more incessant. Drowning out nearly everything after a month putting him on a hair trigger that would snap at the simplest things. He managed to hide the bodies and avoid suspicion well enough for the next four years, but after he graduated high school, he decided he couldn't stay around his loved ones any longer and left.
He devoted much of his adolescence to studying martial arts in an attempt to master both his mind and body. Despite being a near prodigy, this merely made him deadlier and did nothing to silence the voices. He hasn't given up, even though it only seems to add fuel to the fire burning in him, and takes any opportunity to stop at a school of marital arts to help refresh his skills and strengthen his mind.
He briefly served overseas. He was reckless, vicious, and feared. He took any opportunity to silence the demons in his head with the blood of those he could kill without guilt, frequently breaking ranks to do so. He disobeyed orders one too many times though and was discharged, left to resume his wandering ways.
He gets his funds by picking the pockets of the dead, sometimes buying things with credit cards just to pawn them.