- The tortures: a gang member has a bag of broken glass forced over his head and ground into his face and eyes. The main character is drowned (temporarily) in a barrel of horse urine. And when the heroes capture a villain responsible for the deaths of several friends, they play a game called "Scream in Pain 'til You Answer My Fucking Questions," which involves cutting off all of the villain's fingers with a red-hot knife. Once he's answered the questions, they cut out his tongue.
- Nazca. It really says something when it's considered a relief that she was killed before being pickled in horse urine, rather than having drowned in it. And all to send a message to her father.
- Wraithstone, which "Gentles" the mind of anyone who inhales the smoke, nulling out practically all conscious thought and leaving a docile creature without any survival instinct- they won't even eat or shit without being prodded and coerced to. In the first book, the Grey King plans to do this to every single noble of Camorr at once, as revenge. Even the children. Locke and company risk their lives, despite not being initially involved in that portion of the plot, to save their worst enemies from such a cruel fate.
- In the second book, Locke meets a man whose family adopted a Gentled kitten. Locke is appalled, asking why the hell anyone would do that, and later finds out that the kitten came from a litter that was Gentled because some noblewoman's children wanted to torture them because they were bored.
- During the attack on the Poison Orchid, Locke and a few others are assigned to repel boarding parties. They're helped out by some horrific sea-monstrosity that sucks the blood out of some poor bastard through his pores. After that, the boarding party does its best to get the fuck out of the water.
- All marine life on this world is nightmarish, from a 50-ft monster which trails vessels to a creature that telepathically tries to convince sailors to throw themselves overboard. In-universe, the sea is so feared that even a mile-long swim in the outer harbour of Tal Verrar is regarded as near suicide.
- Stiletto Wasps, whose stingers are the size of a grown man's middle finger. Anyone with a fear of bees will cringe when reading about these creatures.
- Most of the powerful people in Locke's world are not the types you want to cross, as they will get their revenge, but Requin takes it to another level. After an attempt on his life that backfired and harmed someone else, Requin went on a Roaring Rampage of Revenge that started with him killing random people and cutting all the skin on the left side of their bodies off, and finished with him taking the man who attempted to kill him, chaining him into a frame, filling the left side of the frame with cement, and leaving the man to die horribly.
- The last man who started a fight and drew blood in the Sinspire was tied down and had his kneecaps cut out and replaced with fire-ants.
- What they do to red-headed girls in Jerem, which is so wrong that even the Thiefmaker- who in Sabetha's own words would "suck a diseased rat's cock for a few coppers," and has no problem murdering pre-teens if he thinks they've screwed him- went out of his way and spent his own coin on hair-dye for her just to keep her safe from this fate. Jeremites pay large sums for red-headed girls so that they can use them in a sick ritual. The girl is circumcised and then raped continuously to death by anyone who will pay the price. People with "rotted cocks" who want them cured will take a turn, deviants who want to sleep with a red-head, and all other sorts of lowlifes will rape the girl until she dies from the trauma they inflict. Apparently it's considered good luck to "be the one riding her when she dies." And the shrivelled cherry on this maggot-ridden cake is that they don't care how old the girl is. Even Sabetha, who is a dangerous thief and con artist, fears this fate so much that she's anxiously awaiting the day her hair goes grey, so she can stop dyeing it to hide her true hair colour.
- The human chess in the second book. Basically, when pieces are taken, a penalty is placed on the piece in question - which can be and often is anything short of actual death, from being brutally beaten to being pelted with rotten fruit. Worse, the spectators are never there for the game, they're there to see the penalties- and occasionally the people who inflict the penalties go too far and kill someone by mistake, and nobody cares.
- The entire city-state of Karthain. It has a ruling government, but it's really ruled by the Bondsmagi, who have magically altered all the citizens as they saw fit. And none of them think that there's anything wrong with that.
- The Ghostwind Isles. Nobody knows how many there are, and there are only nine at the most that people have set foot on and come back from. There are and were three settlements in total on the Isles: Montierre, Port Prodigal, and Hope-of-Silver. Montierre was destroyed in a war, Port Prodigal is alive and thriving, but Hope-of-Silver... it was thriving, until one day every single person in the settlement went missing. No trace of them was found- the only conclusion was that something came and took them all. There were only a few people ever found- sailors, who'd set off in a hurry, and had ended up lashing themselves to the highest point of their ship to escape whatever came for them... and it didn't work, because all of them were found dead, having killed themselves to get away from whatever the fuck it was.
- The Magician's Guild, including the story of why no one messes with them, which coincidentally is why there is no longer an emperor running most of the world: The Guild proclaimed that they would no longer bow to any authority, and anyone who wanted to hire them would have to pay absurd amounts of money, so much so that divine intervention is expected to be more likely to happen than for someone to hire a mage. The emperor decided that he didn't want that, and sent his army. End result, six mages, out of hundreds, dead, and an entire army laid to waste. And then, the mages summoned destruction on a level previously unimagined by man, destroying everything and everyone in the entire imperial capital... except for the throne, which sits empty and intact even centuries later, as a monument to the guild's power. This act led to the empire breaking apart, and centuries of war, famine, and chaos. And the guild gives exactly zero fucks about any of that. The mages are considered the most dangerous people in the world, and if the Falconer mage is any indication of what the average mage is like, then they've not changed one iota since the day they had murdered an entire city of innocent bystanders just to prove they could.
Nightmare Fuel / Gentleman Bastard
The Gentleman Bastard series by Scott Lynch begins as a fairly amusing story about a fictional city's first group of con men. Then the tortures begin... Spoilers below.