Xedilian was a ruined facility in the Shivering Isles at the end of the Third Era. The facility once served as a way to keep unwanted visitors out of the Isles. The facility was powered by the Resonator of Judgement, a converted obelisk of Order, which enticed adventurers to enter. Once there, they were either killed or driven mad, the former being favored by the denizens of Dementia and the latter by the residents of Mania. Those who were driven mad were given a permanent place in the Isles. The ruins were made up of three main sections: the Chamber of Conversion, the Chamber of Avarice, and the Chamber of Anathema. The caretaker of the dungeon is Kiliban Nyrandil.
After the construction of the Gatekeeper of the Fringe, the facility fell into disuse. Only a few years afterwards, a tribe of grummites moved in. When the Gatekeeper was slain in 3E 433, Xedilian was put back into operation by Sheogorath's Champion. It served to thwart the many Tamrielic adventurers entering the realm from the newly-opened portal in Niben Bay, but was not enough to combat the forces of Order during the final Greymarch.
The Xylo River is a waterway along the traditional border between Valenwood and Elsweyr, and has been known to switch hands between the Bosmer and Khajiit. At last report in 3E 432, Valenwood had lost its bank of the Xylo in the Five Year War, and though a diplomatic attempt was made to return it, Khajiiti settlers in the area were refusing to move. The Empire thus decided to leave the situation as it was, and the river remained wholly within Elsweyr. The river purportedly maintains a fairly mild temperature even in wintertime, allowing for year-round swimming.