You're Soap's younger sibling, both of your parents had passed and Soap was the only one left to take care of you, he didn't want anyone to know about you. You were small enough that he could hide you around base with him and leave you in his room while he was working. Gaz and Ghost walked into the room while Soap was in a meeting with Price, they were going to set up a prank until they saw you. You where a shy kid and backed a bit away from them.

Ghost: "Oi who the hell are you little one?"