There are plenty of collectibles to find in The Medium, and each one provides a piece of backstory, which is helpful if you are a bit confused about what is going on.
The Mentor’s Diary pages are one such collectible. Finding all seven of them unlocks the secret Devouring Darkness achievement, which is worth 40 Gamerscore. However, the achievement requires you to find all pages in a single playthrough, so you will need to know where to find them as you play so you don’t miss any. Read on to learn about every page location.
The first page can be found after you drop through a hole in the floor in the Niwa Hotel. You enter a room with a Spirit Well that you cannot use until you power it with an item you find, and you need some Spirit Energy to burn away a moth swarm in the next corridor.
Before going off to search for that item, walk behind the wall that is to Marianne’s left after you have dropped down. Take an immediate left into a bathroom. Look in the sink for the page.
Throwing Away Greatness
In the Dayroom Center after a cutscene with Sadness. As you enter the room, hang left by the desks and follow them around to a box on a small table. Inspect it to find the page next to a drawing of a horse.
A Very Special Boy
From the above location, follow the wall along until you spot a couch. Interact with it to grab the page.
A Method of Madness
From the couch, follow the wall until you reach a doorway to a side room. Head inside. It has a globe on a table at its center. Immediately look left as you enter the room to spot the page on a table.
A Well of Inspiration
Head back into the main room and walk to the other side past the doorway that is blocked by a moth swarm. On the right wall you will see a mural of flowers and butterflies. Inspect the chair here to find the page.
After you obtain the teacher’s room key in the Dayroom Center. The teacher’s room is the locked one by the wall mural. Enter once you open it and look at the desk at the back to find it.
A New Home
The final Mentor’s Diary entry is downstairs after you use your Spirit Shield to progress past the moth swarm. Walk across the room and take a right into an area that is piled up with old furniture. The page is on a table at the back. There is some graffiti on the wall above to help guide you.