Game environments are not built with a ruler and some tape, they are built with imagination and an understanding of what is needed to make the game environment. If you take the time to learn about what you will need to do before you being the process, it will make for better results in less time with less work.
Magical Fiends: When a mage or wizard casts a spell and draws more energy than s/he needs Magical Fiends are drawn to that spot and they feed of the extra magic as long as they can. When someone's magic is being fed off of they can't cast spells as well and they feel weaker. The only way to remove a magicial fiend is for it to be drawn away by someone else's power or to go to the very spot you first cast the spell and kill them