Ok, I have a premise down. Basically, the school is called "The School of Natural Law." It teaches people who have been chosen to success a divine or otherworldly unique entity how to behave as such an entity, and their duties and powers. It's ALSO a school to teach some humans how to act as shrine-keepers and other such important tasks. Many of the deities and supernatural entities are either benevolent, or, impartial. However, there are some entities in existence that are not so benevolent that must learn their place too. It's a wonder how the place doesn't fall apart. As a student, it's your job to try to make it through your instruction alive. 

There is plenty of lore to work off of to keep it interesting.