User blog comment:Lord Loss/Discussion of the Week: Rare Species/@comment-765166-20131201094252/@comment-5043481-20131201104756

I have thought they were bred by the people who built the towers as gaurds of some kind initially, but after the people died/left they stuck around and the breed as a whole stayed there, at least sometimes. The tower is easily big enough to house a huge wyvern colony.