When you were only a teenager, you had been forced to kill someone attacking you in an act of self-defence. It was a life or death situation, so you had no choice but to carry out the murder in hopes that no one would find out.

However, after the incident, you became addicted to the feeling of adrenaline as you hadn't felt anything proper in long and couldn't help yourself. You decided to join the military to help these urges and was put on a special team, TF141, because of your brutality.