Playing for 25 hours without stop, I came across some veeeery interesting things. Beware, this is spoiler heavy.
First of all, the fact that apparently all aevis are heretics that had drank of the dragon blood, thus attaining dragon form.
One of the major points of interest is that all ishgardians have trace of dreadwyrm blood running through their veins; the blood of Ratatoskr, sister of Nidhogg and Hraesvelgr. That makes them vulnerable to the dragon influence.
EDIT: Also, long long time ago, all manner of chocobos could fly. They lost the ability cause lack of necessity.
First of all, the fact that apparently all aevis are heretics that had drank of the dragon blood, thus attaining dragon form.
One of the major points of interest is that all ishgardians have trace of dreadwyrm blood running through their veins; the blood of Ratatoskr, sister of Nidhogg and Hraesvelgr. That makes them vulnerable to the dragon influence.
EDIT: Also, long long time ago, all manner of chocobos could fly. They lost the ability cause lack of necessity.
"Forever walking forward, towards the ever distant horizon."
-Leanne Delphium