Teacher is the 529th chapter of Hiro Mashima's Fairy Tail. As Acnologia is on their trail, the mysterious woman is revealed to be Anna Heartfilia, who along with the five Dragon Slayers came to the future in order to defeat the Black Dragon. While biding her time away from being the caretaker of the children she looked over, she discovered a power that with can seal Acnologia in a suspended time laspe, which in consequence would prevent future despair the latter will commence.