Twins

"I wish, that until I wish otherwise, Karyn was part of a set of identical twins. They would both look like Karyn did five seconds before I made this wish, but would have different personalities, tastes and interests. Despite this, they would be close, to the point where they have an intimate incestuous relationship with each other in addition to any other partners that they have. Both would know about the stone and its ability to grant wishes and I would be the only one who would remember that anything was different." The stone flashed, telling Jon that his wish had been answered.