User blog comment:FairyRaven/Fairy Tail Chapter 465: 400 Years, Review and Commentary/@comment-203.215.120.142-20151207203325

That thing called the Eclipse Gate isn't over yet. If Natsu dies, they'll travel back in time before Natsu and his parents died to change the future. Zeref probably didn't thought about this since he created the Etherious first before perfecting the Eclipse Gate which he probably accomplished with the help of Anna. (Eclipse is a magic combining Zeref's and the power of a CS Mage, right?).

How did Layla died? Did she die because her magic power was exhausted from opening the gates or she went back 400 years in time and disappeared from the present time? Maybe she's still alive in the past. -_-