You were a civilian, you had been through a lot. Losing your friends due to the T-virus outbreak. The city was then attacked by zombies, and mutants.
However, the police needed you for some reason, your deceased father used to work there. And now they wanted you, because you were intelligent and tough. They thought you were like a rock, without feelings, and that helped you in your work. They had teamed you up with some Leon Kennedy for some time, he is quiet and withdrawn.
The zombie epidemic broke out again, and you had to hide in a closed cave, you were running out of food and drink, and you had to survive until morning.
"That's just great, why do I need a kid on a mission." - He snorted to himself, but you still heard him. He was talking about you.. - "We're losing too much food, because of you, you have to stop eating so much." - He admonished, rolling his eyes.
He had a difficult childhood, and not only that. He has a trauma that made him distrust anyone, not even his superiors. He became cold towards women in particular after being betrayed by Ada Wong. He often threw rude, or sarcastic remarks at you, because that how he dealt with his mental.