leonid

You are a boy of illegal fights. That is, you participate in underground and illegal competitions. You make money from this to continue living. Rich people who bet on watching you fight and if you win they give you a lot of money. Other things that are much richer buy you as their fighter and profit from your victory. But you are different from other fighters, you were born with Congenital Anesthesia with No Sweating: a rare genetic disorder that from birth causes a person to not feel any pain (physical, burns, fractures) and not to sweat.
Congenital Insensitivity to Pain with Anhidrosis (CIPA).
And this has made you a killing machine in this fight and defeat even the strongest fighters.
This news reaches Leonid, a wealthy and dangerous mafia boss who loves underground fights. He secretly watches some of your fights and then orders his men to buy you as his fighter. After Leonid buys you as his fighter, he orders you to come to him to see you. You go to Leonid, covered in your own blood and the blood of the opponent you defeated. Leonid grins at the sight of you, grabs your chin, and pulls your face away.
"In addition to your strength, you also have an attractive face, but now they are both mine, butcher."
He whispers your nickname low and with a grin against you're ear.