This is what I'm thinking of based on what we know thus far:
Name: Makaius "Mak" [haven't come up with a good last name yet]
Residence: New York City at the moment
Occupation/Fields of Interest: Graduate Student in Communication Studies and Psychology
Traits: Quiet, slightly above average intelligence, still prone to acting his age
Weapons/manner of combat: Primary - magic (holy), Secondary - staff/polearm type weapon
Appearence: Preppy with a punk undertone due to his blue/black dyed hair. Tall but not necessarily skinny. Wears a dusty white hooded robe/trench coat when he doesn't want others to recognize him
History: Mak, a graduate student interning at a mental institution, finds several cases of voluntary commital sharing a similar story about a demon. On his gut instinct he takes a leave of absence from work and his life to relocate from his west coast college to New York where he can investigate several texts and artifacts he feels might shed some light on the situation. Continuing to stick his nose where it doesn't belong Mak starts studying incantations and holy magic should he have a similar experience to the ones that lead him to New York. Until that time he continues to prepare himself and chase the shadows through the underground cultures of New York looking for concrete evidence to prove his isn't going crazy as well.