The University of Hell

Many of the demons were formerly angels charged with educating mankind and continue their duties in Hell. In what manner they teach to whom they teach is not always clear. However, there are modern demon-worshippers who summon these demons for help in their studies.

This list is by no means complete. As I find additional information I will add it here.

Asmoday	Teaches the art of invisibility to humans as well as mathematics.
Forcas	Teaches rhetoric, logic, ethics and mathematics.
Agares	Teaches all languages
Amy	Teaches the secrets of astrology and of the liberal arts, and gives faithful servants.
Bearded Demon	Teaches the secret of the Philosopher's Stone.
Furcas	Teaches the Arts of Philosophy, Astrology (or Astronomy depending on the source), Rhetoric, Logic, Cheiromancy, and Pyromancy.
Crocell	Teaches geometry and the liberal arts.
Forfax	Teaches astronomy and liberal arts.
Forneus	Teaches art, rhetoric, and all languages.
Nelchael	Teaches astronomy, mathematics, and geography to his fellow demons.
Alocer	Teaches astronomy and liberal arts.
Bifrons	Teaches Astrology, Geometry and the strength and virtues of herbs, precious stones and woods.
Buer	Teaches Philosophy (moral & natural), logic and the virtue of herbs.
Cimeries	Teaches the Sciences, Grammar, Logic, and Rhetoric.
Murmur	Teaches philosophy (absolutely).
Heramael	Teaches the art of healing, including the complete knowledge of any illness and its cure, He also makes known the virtues of plants, where they are to be found, when to pluck them, and their making into a complete cure.
Trimasael	Teaches chemistry, all means of conjuring of the nature of deceit or sleight-of hand, and the secret of making the Powder of Projection, by means of which the base metals may be turned into gold or silver.
Sustugriel	Teaches the art of magic
Hael	Enables anyone to speak in any language he will, and also teaches the means whereby any type of letter may be written. He is also able to teach those things which are most secret and completely hidden.
Sergulath	Teaches the methods of breaking the ranks and strategy of opponents.