Sacred Haven of Debauchery

Swamp, Ar!

Well, just so you know, Fortress isn't overpowered either. It has fast construction and Tazar, but as far as I remember, their territory consumes a lot of movement points, and this is considered one of the main drawbacks of the faction.
There is, however, a trick with a million wyverns, but in HotA there are plenty of these creature banks. If not wyverns, then angels, or giants, or cyclops. This somewhat levels the playing field.