User blog comment:Kogath/Monster Hunter 4 Ultimate for the Nintendo 3DS/@comment-5893858-20141006230051/@comment-5020152-20141007001302

The rivalry between Lagia and Rathalos isn't what I'd consider an actual 'rivalry'. They're two alpha predators that occupy similar niches and thus they fight with one another whenever they happen to appear, which can't be very often.

Selregios, on the other hand, is a Flying Wyvern that is both faster and more agile than the King of the Skies, is brutally aggressive, and actively competes with Rathalos. So I'd say that their relationship is more fitting of the term 'rivalry'.

That said, I think a great title for Selregios would be "Usurper of the Skies".