User blog comment:IamJakuhoRaikoben/Chapter 405: Tartarus Arc: Part 6 - Magna Carta, Review./@comment-24277053-20141020204850/@comment-7418318-20141021094637

We don't know if Layla was the one who summoned them.

From Zoldeo we know that at least one of the three care-takers was able to summon the spirit entrusted to them or the Spirits might also have come through under their own power.

To summon all three at once instead of one after the other when she's already too weak to be a mage would be foolhardy in the extreme. And from what we know about her, recklessness and foolishnes doesn't seem to be Layla's character traits.

Anyway moving on: At first I thought that the girl in the crystal might be Mavis, but now I get the creeping suspicion that we'll only get to see a silhouette of the girl, without seeing her actual identity and it'll serve as a setup for some important development tied into the next arc.