User blog comment:Kogath/Monster Hunter X Discussion/@comment-5963861-20150917203534/@comment-6050823-20150918015821

In all honesty, I suspect they've always been there and just are really haven't been known live there until recently, by us anyway and the Hunter's Guild could've known about them for god knows how long. Also, it shouldn't be forgotten that there is certain districts of the Hunter's Guild and those districts sometimes don't be knowing about certain monsters, such as Mezeporta district knowing nothing about Deviljho.