Magic and Portals
Magic is a mysterious force, wielded easily by the powerful, enigmatic beings most call gods and only somewhat understood by Wizards and Scholars.
What is known is that it is a changeable force, that ebbs and flows as time passes. As time passes, some spells or magical effects can change, and there are researches specifically dedicated to studying these changes and modifying existing enchantments so that they work properly. The occurrence is rare, but it does happen.
One of the greatest magical mysteries of the past are a series of non-functional portals that dot the landscape. These Portals are rare and no one can say exactly how old they are, and they are a constant subject of scholarly debate. They give off powerful magic emanations, and researchers have long studied them and attempted to repair the enchantments they use, but to no avail. It seems the magic is just to alien, too different from today's magic.