A big sister will mostly likely treat u like trash but deep down inside they love you. Sometimes when a baby sibling gets hurt they will most likely care for them like mothers but as a sibling.

A big sister is a little sister that has grown up, and is no longer capable of collecting Adam from corpses. They are in a deep sea diver suit, just like a Big Daddy. They are able to use Plasmids, and have a large needle to take Adam and transfer it into themselves.