User blog comment:FairyRaven/Fairy Tail Chapter 453: A Father's Job, Review and Commentary/@comment-3285005-20150919114837/@comment-7418318-20150919122622

We never did learn what happened to her silver keys...

On one side I'm hoping that she'll give them to Lucy, simply because I want Lucy to have a Caelum.

But then it'd also be a nice touch if she kept them in case she ever met up with her sister. And then she gifts them to Yukino upon their reunion.