Killers and Monsters is the second instalment in the Three Fates Mafia series although it can be read alone. It's a spicy monster romance with a M/M, M/F, and M/M/F pairing.

The review might contain spoilers.

PLOT
Let's be honest: there's no actual plot. If it would be a fanfiction on AO3, it would have the tag "porn without plot" because the main aspect of the book is the sex scenes. There's a bare minimum of plot into which the romance/the sex is nestled into. Serena is the niece of a mafia boss and gets married to another mafia boss - Ian, the Dragon - when she's barely 18 years old, which results in her moving from Italy to California where she lives in a remote castle/villa with her personal bodyguard, Luca, and several other guards hired by Ian. In all those years, she sees her husband only twice, which in her opinion, is twice too much. In her opinion, he's a monster, so when she receives news that he plans to visit her, she snaps. Luca and her plan to kill Ian but they never receive the chance as dark secrets start to appear and Serena realises: her husband isn't as horrible as she thought he would be.

WORLD-BUILDING & MAGIC
There's not much concerning the world-building. It plays on our planet in somewhat modern times (there's no mention of a year) but it incorporates mafia elements and Ancient Greek mythology in the form of Gods, demi-gods, monsters, and the three fates. There's no actual magic but the demi-gods have powers granted by their godly parent, so it can be considered as a type of magic. The entire book plays in a fictional city in California (USA) but there are references to other countries (e.g., Italy) but everything is very superficial.

CHARACTERS
The main characters are Serena, Luca and Ian. There are a few other characters who either appeared in the first novel or will appear in the following books. It is known that Ian is a monster, an actual dragon, while Serena and Luca consider themselves as humans until the truth comes out and it is revealed that Serena is a demi-god.
Serena is "a princess/a queen" and acts like a spoiled child all the time despite being considered as tough and deadly. Of course, she's also utterly beautiful. Luca is so angsty - emo teenagers have nothing on him - with his "my darkness will push her away". He's utterly obsessed with Serena, extremely possessive and brutal. Ian is the only one who has a functional brain cell and uses it occasionally. He's considered as brutal and arrogant as well but he's rather soft towards Serena (and Luca). There's not much depth to any character and some of their actions lack conviction as well. As for their sexualities: Serena is straight, Ian and Luca are bi-/pansexual.

ROMANCE
Insta-lust, obsession, insta-love, and insta-forgiveness. The author gets partly away with it by making all Serena and Luca mates to Ian, and with each other despite being not monsters, but the insta-forgiveness is my pet peeve (e.g., Serena thought that Ian forbid her from leaving the villa for 10 years when it had been Luca who kept her captive there). Their relationship is so utterly toxic (especially the one between Serena/Luca and Luca/Ian) as it's built on obsession, stalking, tons of lies and blackmail. There's also the fact that Luca met Serena as a child, saved her in some alley, and became already smitten with her there. I know that the author wanted to highlight that she's his first love but he's a few years older than her and it has soft grooming/paedophilia vibes to me. While Ian demanded Serena as his "price" when she was just 17 years old while he is an ancient dragon, so there's also paedophilia there. Plus, he dreamed of her as an adult as soon as she was born.

It is a polyamorous romance as all three are in a relationship with each other. It starts as Serena/Ian and Serena/Luca, with Ian/Luca on the side, but evolves quickly into all three being together as they each Ian's mates (and Serena/Luca become mates as well).

As for the sex, I would give it 4 🌶️. It's very graphic and very sexual from the start (although the actual sex scenes happen after a few chapters). If you are into it: two dragon cocks, double penetration (vaginal, anal), threesomes, BDSM moments, actual monster sex (as in Ian in his half-dragon and full-dragon forms), choking, non-consensual voyeurism, degradation play, mating bites, masturbation, breeding kink, Dom/Sub. I'm sure that I forgot something but let's just say that it's very spicy.

TW
Head the trigger warnings that the author already lists at the beginning of the book.

Voyeurism, breeding kink, degradation, double vaginal penetration, erotic photo (consensual and non-consensual), biting, cum inflation, dragon sex, size difference, BDSM, general violence, multiple murders, intimate partner violence, captivity, arranged/forced marriage, attempted rape, paedophilia, (soft grooming), alcohol, alcohol abuse, hangover, unprotected sex, fear of flying, anxiety, mentioned past parent's death, general sexism, soft ableism (concerning mental health), child slavery (Luca gets sold as a child to pay a debt), sex toys, pregnancy (epilogue), blackmailing, obsessional love, stalking, toxic relationship, ...

Please check other reviews for more/additional trigger warnings. These are the ones that I noticed/marked in my Storygraph journal for the book.

TL;DR
Monster romance with a focus on the sex scenes (that are very explicit and graphic). The romance itself is between two men and a woman (all are in one relationship and are each other's mates). Based on the idea "What if the princess fucks the dragon that kept her in a tower and falls also in love with the knight that was meant to save her?" (just with a dark knight).