Grim #1
All credit goes to toidi m'i!
At the first large area with enemies behind building there is roof of other one berried in snow, the grim is in barrel near it.
Tome #1
In next segment of open area there are 2 paths separeted by cliff it would be faster to drop on right side for 1st tome.
Grim #2
Going up from lover area with 2nd tome you will see 2nd grim, just jump somewhere close to it and take it mid jump.
Tome #2
After cave area there will be two subsequent dropdowns you drop only one time, there is tome behind tree.
Tome #3
After dropdown from 2 tome there will be doors to ur left. Tome is behind 3rd one.
lul, there is a 4th tome) in a location with bridge event
As i uderstand if there were not other loot spawning in thise place there would alwais be tome. So the less loot spawning on the map, the more chances for tome to be there. and of course it’s more likely to be no loot on higher difficulties