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