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