The Aergwyll is a high, vast and hilly forested plateau. At the center of the Aergwyll is a deeply forested peninsula that extends into a great mountain lake, surrounded on three sides by the tallest mountains in the Realm and guarded along the south by an expanse of unearthly precipitous drops into the Siddi Mountains below, and from which only lonely Mount Shehelemet reaches to the level of the Aergwyll plateau. Ysgarth Deep is a massive falls that drops nearly 4000' into the Icen River Gorge that eventually flows through the Torc Amret. On the peninsula in the Lake of the Aergwyll is the University of Dwyfyn Coddig, a place of Draechi learning where the Gwybdwyll also guard a secret pool.

Near the densely forested coastline the University are the hanging rocks of the Draechi Magesterium, which hover inaccessible above the lake topped with spired monasteries, housing the ancestors and perhaps last of the great Gwybdwylli themselves who over a thousand years ago used a potent secret to destroy the Horror of Dumnonia. They keep this secret safe.