Wyvern

The Wyvern is a dragon like emblem heartless located in Hollow Bastion, but after the Hollow Bastion keyhole is sealed, they can be found in other worlds. They are quite powerful and attack with claws and a corkscrew attack. They are also known to drop Power Crystals.

They are based upon Wyverns from Final Fantasy, which are ridden by Dragoons...

Could they be the heartless of those who become Dragoon nobodies?