Here is the full list of all 19 Demonologist achievements.
Exorcise the ghost in the Bedlam
Revive your friend with a Tarot Card.
Play on the Bedlam map
Play on the Kurosawa House map
Buy the Lighthouse.
Successfully joined the "family."
Buy the Pub.
Play on the Hospital map
Exorcise the ghost 5 times.
Play on the Cyclone Street map.
Purchase Two Crucifix
Exorcise the ghost once.
Take Two Photos Of The Ghost.
Read EMF Level 5.
Correctly identify the ghost 3 times.
Correctly identify the ghost once.
Die once.
Play on the Abandoned House map.