User blog comment:FairyRaven/Fairy Tail Chapters 338, 339, 340: Review and Commentary/@comment-86.66.207.63-20130706094810/@comment-1359322-20130707120345

They just combined the Celestial Spirit Magic with the Book of Zeref and it is a known magic, Doranbolt and Lahar knows about the Eclipse Gate, so the magic itself might be quite old.

Well i'm not going to further this topic since it's already pointless to talk about something that might never be touch again.