It would be best if you had a substantial populace in The Elder Scrolls: Castles to make a lasting fortress. These subjects do all the work you need to be done on top of populating your castle. The better the subject, the faster the job is done, and the longer each subject can last under your rule. So it’s an excellent idea for every castle to have a skilled populace. Still, there’s a lot more to this than meets the eye.
