User blog comment:Lord Loss/Monster Hunter Theory... Blog/@comment-4361439-20130206182832/@comment-4361439-20130206202950

That would actually make sense, since in mythology, Dragons are indeed thought of as creatures of unparalleled strength as opposed to other animals, meaning only a Dragon could compete with another Dragon. It also makes sense that mostly only Elder Dragons are weak to the Dragon Element, seeing as they're the closest things to actual Dragons we have in the series.