Alexander
Alexander is a student in the field of magery who specialises in magic circles.
During a visit into the university's cellar, he accidentally opens an ornate brass vase releasing 72 demons, imprisoned thousands of years previously by King Solomon. The only remaining demon, Caim, offers to help him recapture the others. In agreeing, Alexander allows Caim to 'tag' his body with his diabolic signature, granting Alexander access to a portion of his power.
Grimoire
Carried with him almost everywhere is Alexander's grimoire - a vast collection of spells, magic circles and notes kept by him over his years at the university. It is locked by two latches and no less than three magic seals which react only to Alexander.
It should be noted that Alexander is not a reference to Aleister Crowley who was born Alexander Crowley.