I picked up the Horror Realms Pathfinder source book in a Humble Bundle, and have been reading it cover to cover. This is my review of the book, chapter by chapter. Chapter 2 is called Strange far places and it's about seven different regions on Golarion that are prone to some type of horror, so I'm posting reviews as I complete each section.
The final section in chapter 2 is set in Ustalav, the classically gothic horror location on Golarion. Ustalav is a well-known region in Pathfinder lore as the home of Tar-Baphon, the Whispering Tyrant, and his 600-year undead empire. Although Tar-Baphon and his empire was defeated by the Shining Crusade in the 3800s, echoes of it remain all across the land, and there are tales of vampires and werewolves and the walking dead even today.
To prevent necromancers from reclaiming equipment or magic from fallen crusaders, many fallen knights were buried by their comrades in unmarked graves. These deaths were officially unacknowledged, and so the graves collectively became known as "honorless graves." Alcrion Tornavich was a knight in the crusades killed by an arrow bearing such dark magic that his soul has yet found no peace, even though one of his lieutenants returned to his unmarked burial site and built a shrine to him.
The town of Satravah formed around the shrine, and that's when things got really bad. Koslav, one of the town's preeminent elders, believes that agents of the Whispering Tyrant are out to steal magic from the shrine. To protect the town's shrine, Koslav and his supporters patrol the surrounding area at night, viciously attacking travelers under the assumption that they're agents of darkness. You may (or may not, depending on how much you pay attention to the real world) think that killing random strangers to protect a shrine representing bravery and holiness seems anathema. Koslav actually realises this, and that's why he removes his victim's eyes: obviously corpses with no eyes don't remember the atrocities they witnessed before death, so it doesn't count. It makes perfect sense!
This pervasive evil has empowered more evil to move into the area, including the Bloodletter's League, a guild dedicated to procuring occult artifacts and human blood for local vampires. Koslav holds public meetings to ensure that the townsfolk support his late night murderous rampages, and pretty much everyone does.
This is a disturbing and almost too-realistic setting. There's a lot of poignancy to the final setting in this book reminding us that ultimately the most horrific of deeds are the results of a just an everyday human.
To me, this is a unique kind of slasher horror story. You know how in slasher movies, the hero knocks on the door of some local to ask about the strange goings-ons, and the local refuses to talk about it and hastily slams and double-locks the door? In Satravah, you can knock on somebody's door to ask about the murders, and they'll enthusiastically tell you all about the murders, and probably invite you to join in that night. The slasher isn't a mysterious and dark figure, it's the town leader, and he's got their support.
This chapter had some good horror locations, and at worst some interesting adventure locations. Between Nidal and Ustalav alonge, Golarion definitely has regions that are primed and ready for a "horror" adventure. I don't think it's much of a stretch to pop any monster from Classic Horrors Revisited into your favourite Golarion region and lure your players there for a few nights of terror. On the one hand, this approach is more liberating than something like Ravenloft, which is saturated with every kind of horror but is literally either a dedicated campaign setting or part of a different plane (depending on which edition you play.) On the other hand, it means there's not just one book for horror on Golarion. I feel like I would want Horror Adventures, Realms of Horror, Inner Sea World Guide, and Classic Horrors Revisited before running a horror scenario of my own. On the other other hand, the variety of Golarion is a lot of fun. Players can wander aimlessly out of Kyonin, the land of the elves, and cross Lake Encarthan only to end up on the shores of spooky Ustalav, with no planar travel required.
This chapter is full of great ideas, settings, lore, and mechanics. The next and final chapter is called "Corruptions and haunts."