Name: Rin Sokuro
Age: 13
Bloo-Type: AB+
Hair Color: Dirty Blonde
Eye color: Gold/Blue [left/right respectively]
Weapon: Kodachi
Style: 破損の嵐 [Storm-of-Tears]

Bio:

His mother a prostitute who grew to old to work and his father a "Jon".
Rin Sokuro was left to die.
He learned to steal and beg to survive, living off of garbage and the filth that the rest of the world cast away.
At the age of 4 his hands were stained red defending himself from an older group of boys.
Taking a simple pipe in his hands and cracking one of the boys skulls Rin learned something; the strong live the weak die.

The next few years he became a small time thug, perfecting his own fighting style, which used faunts and twists, along with speed and agility to attack from ackward angles forcing oppents to fall off balance and kneel before him before the killing blow.

His abilities atracted the Attention of an Elite group know as K.C.I. [Kyoto Cybernetic Inforcers]
They took him off the streets; altered him physical and Genetic structure to allow him to maximize his fighting style.
In return for his abilities they gave him a home among there organization.

Rin became a top assasain and Joined the Elite of the Elite.
Who have earned the nickname "Modern Day Samurai" the all excepted him for his abilities, though they have curbed his bloodlust as best they can.

Rin Sokuro operative name is "Innocent Demon"

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Edit:
I am aware of the resemblance to Naruto I created him to look very much like the character.

Since at the time I was rather obsessed with the series.