The High Passes is an area, located near from Liscor that is inhabited solely by monsters, with the exception of Teriach, and is greatly avoided, if possible.
It is less than a hundred miles away from Celum, and over 400 miles away from Invrisil[1][2]
The monsters in that area are so dangerous that one needs "fighting skills, or insanely high levels – something above Level 30 probably to get out unscathed." [3]