User blog comment:Mckrongs/Monster Hunter 4 for the Nintendo 3DS/@comment-21371438-20130920092409/@comment-4212769-20130920132536

First, the catastrophe system was introduced in third gen (I said that...) with Jhen Mohran and Ceadeus in without being a regular dragon much but having the body structure more similar to Leviathans still being classified as Elder Dragon because of the disaster that comes with them (sand storms, earthquakes, etc.). So Kirin was already there when that got introduced.

Kirin is in the class because of the former way how monsters becoming Elder Dragons without being actual dragons. The Elder Dragon Expert in Pokke said that they are putting monsters in the Elder Dragon group if there isn't enough information about it and/or there is no other class they could be put in by their characteristics.

And second, well that's the way they do that. It's not because of the dangers exactly but because those natural disasters what "can't be the work of a normal monster but only an Elder Dragon". That's probably the reason behind those classifications. This mystical and simultaneously threatening characteristic of these monsters making them special not being put in a normal class.