Webs of the Endangerment
It divides them vertically, not horizontally, as most walls do.
The odd thing about this, however, is that the wall itself is built vertically, not horizontally.
The top half has a gleaming metal facade with corkscrew towers that defy any to cross into the Vale of Annais.
The bottom half, which sticks up into an impossible rocky sky almost opposite direction from the top half, is a crumbling mess. It’s once-proud towers and crenellations tumble lazly, brick-by-brick, into the fairy mists below.
To make matters worse, the fairy mists are below BOTH halves of the Fierce Wall. If you could see through the fairy mists, the Fierce Wall would look like a mad reflection of itself in the water, with both bottom halves conjoined and both top halves sticking defiantly into a double sky with no ground at all.
Falling off either end of the fierce wall is a tricky proposition, because once you’ve plunged through the fairy mists at the bottom, the gravity on the other side grabs you and drags you back into them.
Conceivably you could fall forver, until air friction stalls you in the mists or M. C. Escher builds you a staircase.