"I will help you get rid of the demon. I told you that" Spirit said, he turned the the other students "spirit magic is the hardest to understand. Do not mess with it. A demon, like with Mathias here, will merge with you. 

Spirit....you can work with spirits, but generally at a price. Good spirits merely wish a contract protecting themselves as well as you. Demons...well. 

With spirit, you can create weapons. You can use light like I do. We will forgo the lesson for now. Read your books. Rest until physically training"