The Starter sets have everything you need to build 2 dolls. The Add-Ons are meant to be used with the Starter sets. Sort of a mix and match thing. As of right now, the best match for the Mystical Add-On is the female Vampire starter. It's not a perfect match, by any means. All of us here are hoping Mattel releases the "missing" pieces on their parts website, like they did with the first wave of Add-Ons.