Necromancer

You feel compelled to follow the voice and you head down the left corridor where eventually you come across a demon sitting in a couched position in a circle. He's looking at the chalk that creates the circle around him, before looking up at you. He's a lot bigger and meaner looking than even the demons you've met on campus. He certainly doesn't seem happy to be trapped. You suspect that they summoned this guy up from hell recently.

"Who are you?"
"My real name is unimportant, but you can call me Velzix…and you are the new disciple of Demar's delusional bunch of would be shit starters. They believe that they will be able to take over this school by using the dark arts. And perhaps they may, but such a victory will be fleeting. Mortals lack long term vision. They will not be prepared when the entire world unites against them…but you can be spared that fate. Free me, and I promise you that you will become a powerful force in the struggle ahead."
"While that sound tempting, demons are known for their deceitful nature and infamous for getting around loopholes in so called deals they make." You say.
"Yes, it is something we pride ourselves on…very well I will not harm you when you free me. That is what you worried about isn't it?"
"It had crossed my mind."
"Okay, now you may free me."