Ghosts

These are all the ghosts of the people that died in the cabin and are still bound to the demon

1. the woman that hanged herself
   Her body still hangs outside the cabin when the players arrive
   she got mad from the demon's whispers and saw hanging herself as the only solution
   her presence can be felt near the tree and generally outside
   her voice is mostly despairing, sometimes mourning the players
   she will say things like
     "not even in death i could escape"
     "don't enter"
     "now you are doomed too"
     "how can I stop this horror"

2. the man that tried to escape
   his body lies outside the cabin just outside the demon's reach he tried to escape from the cabin and take a piece of the hidden door with him, but the demon stopped him, killing him his precence is around the same area where 1. can be felt just more quiet he will say things like   "escape from this place"   "it is too late for me, but maybe you can still escape"  "run from here, before it's too late"

3. the sacrificed victim
   his body is in the sacrifice chamber
   he died when the acolyte sacrificed him
   his precence can barely be felt anymore as the demon consumed his sould
   sometimes he can be felt as a distant scream inside the cabin

4. the acolyte
   his body lies in the sacrifice chamber
   he died when he tried to banish the demon he summoned again
   his presence is felt around the house, but he will mostly keep quiet in fear they think he is on the demon's side
   if he says something he says something like
    "banish him"
    "find the book"
    "you can't escape, you need to finish it"

The players might try and contact the ghosts. If they do, they will expose their minds to the horrors of the demon's mind. This leads to the danger of mental scars, in the worst case insanity, but the contact will normally break before that.