User blog comment:IamJakuhoRaikoben/Chapter 357: The Nine Demon Gates, Review./@comment-5580383-20131025195248/@comment-1359322-20131026080514

Well Jellal did know where the Nirvana was hidden so maybe the Magic Council members know some sort of magic or item that can cause great harm to them, but the Council members still aren't aware of it so Tartaros decide to finish them off first.