Yeah that would make sense. He was stolen from Africa as a child and was tossed around in slavery for a while before ended up with the vampires when he was around 16 (and was massive and too intimidating to humans).

That could actually work - her Creator owning him and then maybe she Changed him to save him? I don't know much about her Creator, but if he was the ruthless type, maybe he just got sick of him, or perhaps was intimidated with his size too? I'll go and read her history!