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