User blog comment:Miskos3/Fairy Tail 529: Teacher, Review/@comment-31.132.65.56-20170403135846

Anna calls the place she wants to seal Acnologia in - 時の狭間 (toki no hazama), can be translated to "time between times". The same phrase is used by Ultear a few times when she appeared in chapter 475 (when she says living in between times isn't so bad e.g.). Anna also (when playing the pronoun game) uses another word in this chapter. She calls that thing she discovered and was researching - 概念 (gainen), can be translated to "concept". Ultear uses the exact same word (only in quotation marks) when she described herself in ch.475

It may lead to something.