User blog comment:Phantombeast/Phantom's Ring of Hope - Fairy Tail 384: Attack of the stars/@comment-4728047-20140518015012

I can't imagine that the Celestial Spirit King would not return Aquarius' key to Lucy

to be able to summon the King requires a strong bond of mutual trust between the Spirit and the Mage, so I would think that the King (if summoned) would return the key to the Mage who summoned him

not to mention that Lucy's already impressed the King (back when we learned that Loke was Leo, member?)