User blog comment:IamJakuhoRaikoben/Chapter 480: The Northern Gravestone, Review./@comment-100.15.97.117-20160404212512/@comment-7418318-20160404225313

7.7.x777, seven Dragons and dragon slayers, the Dragons "disappearing" seven years before the story, a seven year timeskip...

I'm surprised that Zeref's and the Dragons' time was 400 years ago and not 777 years ago. ^^