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