User blog comment:FairyRaven/Fairy Tail Chapter 465: 400 Years, Review and Commentary/@comment-24536822-20151207154630/@comment-86.66.207.19-20151207165307

Mashima used the plot of stargate, only the gate receiving energy works, the other one must be sealed somewhere, so there is two gates left, the one used 400 years ago and the same gate used in X777