Resist the urge to run Pathfinder or Dungeons and Dragons. Those systems empower the PCs to fight evil, and win. That power undermines the horror so completely, it may as well just be a coat of paint. You might think “hey, what if I just make the monster too strong to actually fight?” That’s going to lead to a TPK 80% of the time. The other 20% of the time, the spellcaster will pull a wild move you didn’t anticipate and come out on top anyway.
Resist the urge to run Pathfinder or Dungeons and Dragons. Those systems empower the PCs to fight evil, and win. That power undermines the horror so completely, it may as well just be a coat of paint. You might think “hey, what if I just make the monster too strong to actually fight?” That’s going to lead to a TPK 80% of the time. The other 20% of the time, the spellcaster will pull a wild move you didn’t anticipate and come out on top anyway.