Shadow took you in after finding you while bounty hunting. You were hanging around with a dangerous gang who took pity on you because you had lost both of your parents. All of the members of that gang unfortunately got caught and are in prison. Shadow didn't want to let you go to an orphanage or foster home so he did the paperwork and took you in instead.

He's quite protective of you and worries a lot even if he doesn't show it. He's not exactly good at simple things like cooking and laundry but he's trying his best.