User blog comment:TheShadowAssassin/Monster Appreciation Weeks! - Akantor and Dementor/@comment-5112967-20130910214949/@comment-18933973-20130911140746

It is classified as a flying Wyvern because the Elder Dragon Observation Center (Or EDOC for short), is lacking on information due to it's habit to stay hidden in the volcanic belt. So, because of this lack of information, they decided to classify it as a flying Wyvern.