I find Magearna a bit interesting from the info on Bulbapedia where her true self is the "soul-heart" which contains her artificially created soul. This can mean that the rest of the body that lets her interact with the world can be changed to have different looks and uses as long as the soul-heart can connect. This can lead to a side event where Regigigas tries to create some more Regis or just wants to give her options but allows Megearna to temporarily test the body's. She would get along quit well with Mewtwo since both were created by humans. When she does eventually gives birth will Maple need to construct body's for the new Magearna for them to occupy since they would be just "soul-heart" orbs.