Cania
Cania is the eighth layer of the Nine Hells. Cania, like Stygia above it, is a bitterly cold realm of glaciers and howling ice storms. Mephistopheles holds court here with the ice devils that make up his retinue. Operating from his great tower, the icy citadel of Mephistar, he conducts a never-ending series of experiments that expand his understanding of arcane magic and of the planes of existence.
Cania is essentially an enormous laboratory. Mephistopheles and his devotees prefer to conduct their studies in a wasteland where they can unleash gouts of arcane energy without destroying anything important. Experiments involving new spells, new magic items, and other innovations for the infernal arsenal regularly cause localized cataclysms in this place.
This activity attracts numerous spies despite the inhospitable environment. Merely observing Mephistopheles’s disciples at work can provide insights into the nature of their research and the discoveries they have made. His court is constantly alert for agents from Dis, since it greatly pains Dispater that Mephistopheles might come across a scrap of information that he doesn’t possess. A number of renowned archmages, including Mordenkainen, have at times found their way into this realm on a search for forgotten lore or in the hope of confirming a theory of arcane magic.
Libraries and other places where arcane knowledge is recorded or contained are scattered across Cania, mainly to ensure that a single disastrous experiment at one location can’t destroy the evidence of all the work conducted at other sites. In his pursuit of ever more lore, Mephistopheles combines his prodigious intellect with his obsessive nature. This combination of traits enables him to delve far more deeply into a topic than most ordinary wizards can even conceive of. Even the tiniest of trivialities is fascinating to him. Sometimes, however, the business of the Nine Hells forces him to relinquish direct oversight of a project. When he returns to his research, a new mystery might capture his fancy, while the older project continues to move forward without his oversight or interference.
Here and there, tucked away in Cania’s terrible environment and similarly buried in the immense bureaucracy of the Hells, stand long-isolated citadels occupied by sages and spellcasters toiling away at some seemingly forgotten endeavor. The supervisors of these projects might have achieved incredible results that they patiently wait to share with Mephistopheles the next time his attention points in their direction.