The Zul Mountains, or Sierra Zul are an intermediately tall mountain range that are the most western mountains of Zarhuy. They provide water for ecosystems in western Zarhuy.
They are between the arid Bareds to the north, and the waterlogged swamp of the Saahdons to the south. The (relatively) highland forests and jungles of the Viborg Forests are to the east, with the coast and the Alan Ocean to the west.
The tall Zul Mountains provide ample rivers and trap clouds that rain over the highlands to the east. This turns what would be highland plains into a lush forest and even a highland jungle as water gets trapped within the hills and form lakes and marshes.
Much of the water does drain to the south into the Shaa delta, which adds to the water pouring into the region, greatly contributing to the immense wetland swamp known as the Saahdons.