Dolls don't... exactly have standard blood relations, even if some are "siblings". Keep in mind, they're beings from another world who look human and work like humans in some ways, but they aren't.

Also, the nail weakness doesn't exactly work like that. It's only Doll Hunter nails, and while the shape of the nail is part of it, regular nails are fine and simply touching even a Doll Hunter nail, while potentially discomforting, isn't enough to harm them. It's having Doll Hunter nails shot into them is what hurts.

I'll be getting the OOC up after I get my Doll Master posted later, but the IC won't go up immediately so there's no need to worry about that.