User blog comment:Hikaruyami-having fun*/Get To Know Them/@comment-1194826-20120609184948/@comment-1194826-20120610013431

Twister: but why does this island appear every 50 years? another thing. why stay hidden from the rest of the world to begin with?

Whirlwind: might be because half-demons during that time were disliked among most of the populous.