Warens are the locations in which weilders are trained. This is where they are molded into, what many would say, the best warriors in the world. Here they hone their mind, train their bodies, and understand their spirit. Here they become warriors.
As a new member of a magical organization you get 1-3 magical scrolls to do with them whatever you want. They are unmarked and contain spells you dont know and will only find out at the moment of reading=casting.