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