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
Successfully joined the "family."
Revive your friend with a Tarot Card.
Buy the Pub.
Buy the Lighthouse.
Play on the Hospital map
Purchase Two Crucifix
Exorcise the ghost 5 times.
Play on the Cyclone Street map.
Exorcise the ghost once.
Take Two Photos Of The Ghost.
Correctly identify the ghost 3 times.
Die once.
Correctly identify the ghost once.
Read EMF Level 5.
Play on the Abandoned House map.