User blog comment:Miskos3/Fairy Tail 539: World Destruction, Review/@comment-7418318-20170616061451/@comment-4933386-20170616165635

Remember this is the last final arc, Lucy and Yukino and possibly Angel (previously a CS mage) could work together to try to stabilize it from one end.

well it's gonna be a modified version of Eclipse gate, MAYBE created by the royals or even Anna... she might intend to go back to her timeline so she created one for backup.