These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Author Appeal: An awful lot of the female characters in this series are prostitutes - and large chunks of the text are devoted to discussing their role, their lifestyles and what exactly they do for a living. Reaches cringe-worthy levels in the second book with hundreds of women queuing up at brothels to earn a living.
For what it's worth, when an interviewer asked Weeks which character he most identifies with, it was Momma K.
Justified in that because of how the city was set up, any non-Sakage endorsed female will end up raped at one point or another, you may as well get paid for it. They needed the safety... It makes more sense in universe.
Considering his wife works/ed with them as a social worker of sorts, it could be that he's simply very familiar with the lifestyle. Write what you know, indeed
Prostitution is also not really portrayed as a 'good' thing either. It all makes sense in the context of the book. That said, all of the main female characters are described as attractive, even Elene once one can look past the scars.
Hu Gibbet is widely considered the second best assassin in the land, but informing him he's second best will result in your own drawn out execution. Unlike the cold, business-like Durzo Bint, Hu Gibbet is a sadistic monster who derives pleasure from his work, and while the former makes every effort to avoid collateral damage, Hu Gibbet goes out of his way to butcher everyone in the vicinity on his jobs. At one point,Hu Gibbet kills one hero, Logan's, entire family and household and gruesomely strings up the corpses for everyone's viewing pleasure. His apprentice, Vi, fairs no better under him and has been the subject of verbal, physical and sexual abuse for her entire tenure as his student
Roth, once known as Rat, is another. The son and Bastard Understudy of God King Garoth Ursuul, Rat was a sexual sadist who had raped children of both genders since he was young. In the present, Roth betrays his home kingdom to his father's soldiers, leading to many deaths, and is fond of killing peasants so he can eat them.
Finally, God King Garoth Ursuul presides over a legacy of rape, torture, murder and slavery. Garoth attempts to rape or force the submission of any woman he comes across and makes those hes tired of into furniture. Under his reign, widespread war crimes are common, and people are killed or raped at the drop of a hat. Garoth's entire reasoning? It Amused Me.
Downer Ending: YMRMV (Your Mileage May Really Vary) on this one, but this troper found the ending to the series, for Kylar, to be rather depressing. He has lost the woman he loved, and as far as he knows their unborn son, and is still carrying the Black Ka'kari which will make sure that he outlives every one of his friends and any family that he manages to create, and means that one day he could end up as bitter and broken as Durzo Blint was at the start of the series. And despite Dorian's rather smart move of transplanting Kylar and Elene's unborn son into Jenine Gyre, there's no guarantee that Kylar will ever actually get his kid, since only Viridiana figured it out and she has absolutely no proof beyond her own speculation, and Dorian can't back her up as he went insane, it's possible that Logan and Jenine will not believe Viridiana and believe themselves to be the boy's parents, meaning Kylar will either never know that his son survived or he'll lose him to his best friend. And with Elene dead the ending implies that Kylar will end up with Viridiana, which is a match that I felt should have been made much earlier, but since it took Elene dying to make it happen it felt like Viridiana is a next best choice for Kylar, which will likely make their relationship difficult, and inevitably he will watch her grow old and die (Which as The Mayor from Buffy told is, is not something that makes a healthy marriage.) To me, the ending felt like a Downer Ending and Pyrrhic Victory for Kylar, yet it's presented as a Bittersweet Ending.
Foe Yay: Rat AKA Roth and Kylar. It's canon that Rat wanted to engage in hatesex with Kylar to show his dominance. Rat also kept hassling Kylar and attempting to get Kylar to become part of his harem. Kylar's first kiss was also with him (albeit all part of a plot to "seduce" Rat and kill him). Many years later, Rat tells Kylar that he never believed Kylar died, and he was constantly thinking of him and how he wished to get revenge on him.
Fridge Brilliance: From Durzo's point of view, love is indeed a noose- to his loved ones.
The book is about a killer and his master, what do you expect? In-book examples include the sight of Doll Girl, after being brutally battered and abused by Rat horrifying Azoth, a child hardened by violence and similar abuse towards other people in the Warrens, to vomit and panic and Khali sweeping through ranks of men, driving them to deaths induced simply by probing them mentally and attacking their weaknesses. Even Solon, who insists on taking Odysseus-like precautions to ensure his safety, falls victim to it.
The descriptions of the Ferali also:
Fearsome creatures created from the living bodies and souls of tortured people. Summoned together by Vir magic they are like mythical remote-control tanks that have gnashing mouths over every inch of their body that clings to anything they even briefly touch and then devours it (mostly people). It then assimilates their bones, tissue, and weapons and grows larger/stronger/spinier.
They shape-shift into whatever form they feel is best for the current situation (complete with descriptions of snapping and relocation of bones and muscle) and, while starting out fairly small (~10 feet tall depending on form) quickly grow with every new person they eat to become towering giants, even while walking on four legs.
Oh, also they instantly heal all physical wounds (shortly before devouring the inflicter of said wounds whole and turning them into an additional bicep) and magic bounces straight off of them. The only known thing that can damage them is the black ka'kari ("The Devourer", which can shear and destroy almost anything it touches), which can cut off an arm/leg/tendril/spikey-club-made-of-warrior-flesh.
But then they just right on eat the fallen limb up again and are complete once more.
Their only true weakness is getting as far away from them as possible. This is because they're primarily weapons of war due to their appetites (and the high supply of enemy soldiers on which to chow down on). They quickly starve and devour themselves to death if they cannot find something else to eat every few minutes.
They're made worse by the fact that it appears the people used in the creation of the Ferali have their souls tied to the creature until it dies (or at least the first person whom the Vir magic ceremony is performed upon to turn them into a Ferali). So while the Ferali appears as a mindless monster under the mild control of the Vir and an evil spirit summoned during the ceremony, the tortured person/people sacrificed to create the creature are still very much sentient and feel all it's pain and hunger, but are often too mad from the torture the transformation has had on their body to assert any form of control.
When Kylar and Vi find out what the Godking kept in his bedroom...
Some of the things Dorian does as Godking Wanhope. Raising krul, raping young girls, murdering unborn children...
One-Scene Wonder: Viridiana in Book 1 only. She is mentioned a couple times and does briefly appear at the Jadwin's party. But she only gets one real scene which is probably the funniest in the book.