User blog comment:IamJakuhoRaikoben/Chapter 406: The Girl Within the Crystal, Review./@comment-166.137.246.123-20141108040401

Perhaps Mavis's real magic is a type of Soul Magic. Allowing her to astral project herself. It would explain her ability to walk on water, and the reason she can only seen by those who bear Fairy Tail's mark. Perhaps there is a fairy on Tenrou and she stays there with itm