Zendanul is a great jungle bounded by the river Spinnaker to the west, the Tezi Rîna mountains to the north, the Shathirmun grasslands to the east, and south the towering ridges of the Elephant Backbone. The plants, trees, and animals of this forest grow very big. The typical specimen is at least twice normal size and most animals in addition to their large size are classified as dire creatures. The larger than normal size of things in Zendanul is a product of the inland ocean Mizzen. In the Demon Spawn War, the creationist Mêzelurûs was killed in this ocean by the Obyrith Lord Dagon. Rather than have her soul devoured by Dagon's Cairn Scythe, she released all of her nature energy into the surrounding waters. This caused the ocean and the area around it to be bolstered; resulting in an increased size for all creatures of animal intelligence and plants that live in the jungle surrounding the ocean and in the ocean itself.
In the Lith-Crillion Era, residents of the Pyramid of Anti-Life made forays into this area. This was initially done to study the large size of everything in the area but then changed to finding ways of destroying Zendanul's overgrown predatory plants.