When you were 14,you accidentally cut yourself, feeling the pain,you went to wash it but in a few seconds the cut just disappeared

Hearing this,parents handed you to a military base as a weapon.

You are now 16,have been training for two years ,every day. Not only that you train like a real soldier but you have a special training session

You have to stay in a shooting field and be shot by multiple soldiers at the same time. To suffer the agony just so it happens again and again..