The Serpent's Sin: A Steamy Dark Fantasy Romance

Bloodlines #2

by Kathryn Ann Kingsley, Desireé Ketchum (Narrator)

To destroy the vampires who killed her family… she must become one of them.

Nadi is trapped in a deadly alliance with Raziel Nostrom. After a honeymoon soaked in blood and desire, they make a pact—to take down his criminal family together.

Now Nadi is at the heart of the Nostrom empire, pretending to be a vampire. If her act slips even for a moment, they will tear her apart.

Raziel holds Nadi’s life in his hands. And her heart… His wicked smile sets her body aflame, drawing her closer and closer. Still, he is a born killer—alluring and utterly ruthless. He could turn on her in an instant.

But Raziel is not the only one in his family with a taste for betrayal…

When his brother and sister approach her with proposals of their own, Nadi faces a desperate choice. Will she stand by Raziel, as the world turns against him? Or seize the perfect chance to destroy his family forever?

A thrilling and addictive dark vampire romance, the Bloodlines series is perfect for fans of Carissa Broadbent, Keri Lake, and Kaylie Smith.

Genres: Fantasy, Romantasy, Fantasy Romance, Vampires, Enemies To Lovers, Dark Romance, Spicy

Audible Audio

Published January 23, 2026

About the author

Kathryn has always been a storyteller. Years of scriptwriting for performances on stage and for tourism in Boston led her to writing romantically dark, fantastical tales, which was an obsession of hers that began once seeing The Phantom of the Opera at a young age.

When she isn’t penning new villainous leads, she works in video game development. There, she has been everything from Creative Director to Chief of Staff, Design Manager, Executive Producer, and Principal Writer for various companies in the industry.

She shares her antique home with three very fluffy animals and one very patient and loving husband.

Reviews

[Nicole is Reading Fantasy · Rating 5 out of 5]

THIS is how you do a sequel!

They’re enemies; they’re allies, but most importantly, they’re unhinged lovers.

The Serpent’s Sin picks up right where The Serpent’s Bride left off and begins a spicy new alliance between Nadi and Raziel.

Like its predecessor, The Serpent’s Sin is dark and sexy, with violent and high-stakes encounters, toxic family dynamics, morally black characters, and steamy tension and spice between our leads. This book dives deeper though, giving us some needed character development and growth. We learn more about Raziel’s childhood, his complicated history with his family, and how it shaped him into the man he is today. Meanwhile, Nadi struggles to reconcile her growing feelings for Raziel with her decades long mission for revenge, bringing into question her allegiances and her own self-identity.

Will Nadi and Raziel be able to accept all the conflicting parts of themselves and each other?

I can’t wait to see how the story concludes in book three!

Thank you NetGalley and Second Sky for the e-arc in exchange for my honest review.

[Isabelle · Rating 5 out of 5]

Me thinking this was a duology 🤡 But I’m glad it’s not over, because WOW!

🖤 “Nadi… I believe you’ll get your wish.”—“Because one way or another? You will be the death of me…” 🖤

Now this right here, this is how to do a sequel! Way too often there is a steep drop off in enemies to lovers series, where the enemies become lovers too soon and all the tension dies. But Raziel and Nadi continue to have insane chemistry throughout all the scheming, lies, and betrayals in The Serpent’s Sin.

This book picks up right where The Serpent’s Bride left off. The stakes are higher, the spice is spicier, and the characters are even more morally black than usual. Nadi and Raziel have come to a very tentative alliance; neither trust each other, but they also can’t resist each other. The world building and character development really hit its stride this book as well. This is truly such an underrated romantasy series! I need book 3 immediately, please and thank you. 🖤

Huge thank you to NetGalley and Second Sky for the ARC!


Pre-read:
I absolutely ADORED the first book, so I was thrilled to get this arc! I’m ready for more Raziel 🖤

[makayla 𐦍 ⋆˙⟡ · Rating 5 out of 5]

5 🌟 “𝖨 𝗁𝖺𝗏𝖾 𝗇𝖾𝗏𝖾𝗋 𝗐𝖺𝗇𝗍𝖾𝖽 𝖺𝗇𝗒𝗈𝗇𝖾 𝗌𝗈 𝗏𝖾𝗋𝗒 𝖻𝖺𝖽𝗅𝗒 𝖺𝗌 𝖨 𝗐𝖺𝗇𝗍 𝗒𝗈𝗎, 𝗆𝗒 𝗅𝗂𝗍𝗍𝗅𝖾 𝖿𝖺𝖾…” 🩸

The first book was good but this was even better! Mafia-style vampire clans, fae and alliances. I am so obsessed with this world!

We jump in immediately after that unhinged cliffhanger (thank god), and the plot thickens like crazy! Every layer we peel back just shows how wildly dysfunctional the Nostrom family is. The Raziel/Nostrom tension? The Raziel/Nadi tension?? Ate it up. And Nadi being a shapeshifter is such queen behavior I love it

Volencia??? EAT SHIT BABE 💋

UGH when you slowly start to learn about the extremely traumatic past of the mmc who’s so morally grey and has done a lot of fucked up shit and you’re supposed to hate him but now you understand why he is the way he is and have fully cracked for him and fallen head over heels 😭💘
Every. Single. Time.

The pacing is fast, entertaining and of course ends on another cliffhanger that had me screaming at my kindle!!! 🫨

My attention was gripped, Kingsley killed it with this one 🙂‍↕️🤏🏼 I can’t wait to see where this story goes next! 🫠

“𝖶𝗁𝖺𝗍𝖾𝗏𝖾𝗋 𝗁𝖺𝗉𝗉𝖾𝗇𝗌—𝗐𝗁𝖺𝗍𝖾𝗏𝖾𝗋 𝗒𝗈𝗎 𝗌𝖾𝖾, 𝗐𝗁𝖺𝗍𝖾𝗏𝖾𝗋 𝖼𝗁𝗈𝗂𝖼𝖾𝗌 𝗒𝗈𝗎 𝗁𝖺𝗏𝖾 𝗍𝗈 𝗆𝖺𝗄𝖾—𝗋𝖾𝗆𝖾𝗆𝖻𝖾𝗋 𝗐𝗁𝗒 𝗒𝗈𝗎 𝖼𝖺𝗆𝖾 𝗁𝖾𝗋𝖾 𝗂𝗇 𝗍𝗁𝖾 𝖿𝗂𝗋𝗌𝗍 𝗉𝗅𝖺𝖼𝖾. 𝖣𝗈𝗇’𝗍 𝗍𝗋𝗒 𝗍𝗈 𝗉𝗋𝗈𝗍𝖾𝖼𝗍 𝗆𝖾 𝖻𝗒 𝗌𝖺𝖼𝗋𝗂𝖿𝗂𝖼𝗂𝗇𝗀 𝗒𝗈𝗎𝗋𝗌𝖾𝗅𝖿. 𝖭𝗈𝗇𝖾 𝗈𝖿 𝗍𝗁𝗂𝗌 𝗁𝖺𝗌 𝗏𝖺𝗅𝗎𝖾 𝗂𝖿 𝗂𝗍 𝗆𝖾𝖺𝗇𝗌 𝗅𝗈𝗌𝗂𝗇𝗀 𝗒𝗈𝗎.” FUCKK DUDEEE

[Meghan · Rating 5 out of 5]

THIS IS HOW YOU DO AN ENEMIES TO LOVERS SEQUEL! This series is easily one of the best vampire romances I have read in a while. The first book left off at the biggest cliffhangers ever, to the point where I wasn't sure if I wanted to throw my kindle across my room or cry while clutching it in my arms. I'm pretty sure I did both. While I wasn't as dramatic as I was last time, because now I know that this series will most likely end in a cliffhanger each time when finishing, I was prepared.

Book two picks up right where book one left off. Now that being said, I don't want to say I saw the ending of book two coming, because even though it felt like so much went on in this book. It felt like I read a few chapters and, BAM! ending. There were some parts that absolutely through me for a loop and made me hate Raziel's family so much more than I did before. This one also shows a side of Raziel that you didn't see in the first book either. Even though I will always be hot for bad daddy vamp, you really see Raziel of more than what is on the surface and also the way he opens up to Nadi about his past with his family. Even though this is very much Nadi's story, this has definitely become Raziel's story as well.

I honestly cannot wait for the next book and to see how far they are willing to go to get their revenge.

*Thank you to NetGalley, Second Sky, and the author Kathryn Ann Kingsley, for the ARC!*

[Shannon Farley · Rating 5 out of 5]

“That’s not a good idea.” “Absolutely not,” he conceded. “But I find I’m developing a taste for bad ideas lately.”

⭐⭐⭐⭐.5
🌶️🌶️.5
Release Date: Jan 23rd,2026

This series has been such a fun ride so far! Kathryn is absolutely nailing the overall story balance that we all crave in a Fantasy Romance. A plot that has you on the edge of your seat, wondering how everything is going to play out. A romance that is so realistic and tension-filled that integrates so well with the progression of the story. Characters filled with depth and mystery that you can spite or root for. World-building that is detailed without being repetitive or over-complicated. And a magic/fantasy system that is unique and adds a luxurious dynamic to the overall story.

I am so rooting for this couple and their revenge! This book picked up right where we left off in book one, and wow, it started out with a bang! 😉 I loved seeing their romance build and our FMC and MMC try to navigate how to work together. We also got a lot of political dynamics and hidden agendas revealed.🔥And of course some yummy Spice! This was a fabulous continuation of book one! I will be anxiously awaiting book three to see what dynamics these two are gonna have to face next!💖

Thank you, NetGalley and publishers, for the ARC read opportunity!

[Mai ༊*·˚ · Rating 4 out of 5]

4.25 ★— Is it objectively fucked up to fall for the man who killed your family? Yes. And only Kathryn Ann Kingsley could make me read a romance dynamic like this and have me fully accept it.

As a sequel, this story picks up right where the first book left off, with Nadi facing Raziel and having to navigate their new dynamic now that he knows about her deception, her abilities, and her fae identity. I thought this transition was handled very seamlessly!

Much like in the first book, we get Nadi scheming and playing everyone around her, but now with the added factor of Raziel very much in the mix, which I really enjoyed. These two make a great team, and no matter how much of a villain Raziel insists he is, that man was absolutely down bad for her from page one of this book, which was a delight.

I liked how the plot expanded here and how much bigger everything felt as Nadi learned more about the forces and figures surrounding her. I especially loved that even with her secret revealed to Raz, she remains a spy through and through, and that even hedoesn’t fully grasp the breadth of what’s unfolding as the story progresses.

The smutty scenes here were fun, and I appreciated the variety in how they were used. As Raz and Nadi grow closer, the way they share intimacy also shifts and evolves, which made those moments feel more meaningful rather than repetitive.

The book ends on one hell of an ending, leaving everything feeling open while still clearly setting up an exciting next chapter! I genuinely cannot wait to continue this series.

_________________

Thank you to Second Sky Publishing for the ARC.

[Leanna Streeter · Rating 5 out of 5]

I am absolutely feral for Nadi and Raziel, and The Serpent’s Sin was somehow even better than book one.

This is how you do a sequel. It picks up right where the first book left off and immediately throws you back into the danger, tension, and morally gray chaos of this world. The pacing is tight and immersive, with higher stakes and a story that never drags.

The relationship between Nadi and Raziel deepens in the most compelling way. They’re enemies, allies, and lovers all at once, and their dynamic is intense, layered, and addictive. The tension is still very much there, but it’s paired with growth, trust, and moments that genuinely strengthen their bond.

One of my favorite parts of this book was the character development, especially for Raziel. We get more insight into his past, his family, and the experiences that shaped him, which adds so much depth to his character. Nadi’s internal struggle between vengeance, loyalty, and desire also continues to be a standout, and I loved watching her navigate those impossible choices.

Between the political intrigue, toxic vampire family dynamics, and dark, seductive atmosphere, this book kept me fully invested from start to finish. And while the ending definitely left me anxious for book three, it was also satisfying and felt like a solid progression rather than an emotional cliffhanger.

If you love dark vampire romance, morally gray characters, and enemies-to-lovers energy that evolves into something dangerous and devoted, this series is absolutely worth picking up. Thanks to Second Sky for the gifted arc.

[Plottwistsandchill · Rating 5 out of 5]

This kicks off exactly where we left Nadi & Raziel at the end of book one. This is how you do a sequel...I stayed up until 2 AM because I just had to finish it! I loved how fast-paced it was, constantly moving forward, with twists and turns unfolding in every chapter. The romance and spice hit just the right level, adding the perfect amount of tension throughout.

The revenge storyline and all the scheming within the vampire family were brilliant, with loyalties constantly shifting. You never know who to trust, who's working with whom, or what is manipulation versus true honesty. This is everything I love in a dark fantasy book. The messy enemies–allies–lovers dynamic was done so well that Nadi & Raziel’s relationship had a believable shift instead of a straight flip switch of feelings. They had a palpable “touch her/him and die” energy without it feeling overdone or overly dramatic. I absolutely ate this up.

I still adore Nadi... she is so smart, capable, and badass. I didn’t think I could love Raziel more, but getting insight into his past added so much depth. What he went through growing up was awful, and it really made me hate his family even more.

The last part of the book was a total rollercoaster. I really thought this was going to end as a duology, but no... I was left on ANOTHER cliffhanger! Rude!

Honestly, I am so excited for more Nadi & Raziel interactions. Too many questions, too many loose ends that need tying up (I’m looking at you, Mael & Lana). Bring on book 3 I know it’s going to be the wildest of them all!

Thank you to NetGalley, Second Sky, and Kathryn Ann Kinsley for this ARC in exchange for an honest review.

[bookishy · Rating 4 out of 5]

The Serpent's Sin is a sequel to Serpent's Bride, one of my top reads of 2025!

I absolutely love Nadi, she is vicious and perfectly morally grey! I was a bit disappointed with Raziel's scheming in this book. I was expecting more from him, and it felt like he was outwitted at all turns. Even though Raziel and Nadi teamed up I felt Raziel's family was always one step ahead of them, which was a bit frustrating - I wanted more from them since they were so cunning in the first book.

Raziel and Nadi's romance is still deliciously dark, with Nadi's thirst for revenge and Raziel's monstrous nature making the romance all the more interesting.

I enjoyed it a lot, but I was hoping for it to be a duology, and now I have to wait for book three after that AMAZING ending.

Thank you for the eARC to NetGalley!

[Nawelle Feral Reader Books · Rating 5 out of 5]

Thanks to NetGalley and Second Sky — especially Noelle — for sending me The Serpent’s Sin in exchange for an honest review.

If Serpent’s Bride was a dark descent into obsession, The Serpent’s Sin is the point of no return. The masks are off, the blood is thicker, and every line between vengeance and devotion blurs until it hurts to look too closely.

Book two literally picks up where book one ended, throwing us straight back into the chaos, danger, and uneasy alliance between Nadi and Raziel. There’s no easing in, just a plunge straight into blood, politics, and betrayal. I devoured this book in under three hours; it was that riveting.

Nadi and Raziel’s alliance...if it can even be called that has always been built on violence, lust, and impossible choices, but here it deepens into something far more dangerous. After pretending to be his vampire bride while plotting his destruction and being found out, Nadi becomes both weapon and weakness, and Raziel… Raziel becomes the kind of monster you can’t quite stop caring for.

“Nadi… I believe you’ll get your wish.” Raziel paused as he caught his breath. “Because one way or another? You will be the death of me.”

This book is tense, brutal, and weirdly intimate. The power dynamics are razor-edged but never gratuitous; every moment feels deliberate, psychological, earned. Kingsley has a way of writing depravity and tenderness in the same breath - and somehow making you ache for both.

There’s a shift here that I didn’t expect: Raziel’s layers crack open, and what spills out is both horrifying and human. His past, his conditioning, the glimpses of who he could have been, it’s all heartbreak disguised as monstrosity. And Nadi, gods, she’s feral with grief and rage but still capable of compassion, even when it damns her.

Kingsley’s pacing is on fire. There’s rarely a moment to breathe as new revelations, betrayals, and power shifts constantly come to the surface, every thread tightening and weaving neatly into the wider story. The entire book feels dangerous like it’s holding a knife behind its back. The dual POVs were perfection; we watch both characters unravel and rebuild in tandem, their arcs colliding in all the best (and worst) ways.

The Nostroms are so dysfunctional and treacherous it’s almost astounding. The layers of deception, plotting, and revelation are pure insanity - but I devoured every page. Some plot to survive, others to rule, and the rare few are playing a game no one else even realises exists, pulling strings others don’t yet see. As a fantasy reader, the way Kingsley fuses mafia-style clans with vampires, fae, and political machinations is utterly addictive. Every alliance, every loyalty, every whispered threat had me hooked.

“Welcome to the Nostrom family, darling. Where loyalty is always rewarded with torture and death.”

“The dance of deception never ended in this family.”

At the centre of all this blood-soaked chaos is the evolving relationship between Raziel and his sweet little fae murderer, Nadi. It’s a connection that should never exist because it it too fraught, too broken, too poisoned to survive; and yet it grows more intricate and compelling with every page. They are equals in ruin, bound by violence, need, and something dangerously close to love.

“They were destined to destroy each other. One of them would end up dead. A duel to the death. And it was delicious to him. He would have it no other way.”

I hated to love Raziel in book one, but book two has me falling in love with the monster. By the end, I wasn’t sure whether to scream or applaud. Their bond isn’t romantic in the traditional sense - it’s ruinous, consuming, and built on the kind of trust that tastes like blood. But it’s theirs. And I can’t look away.

If Serpent’s Bride asked what you’d do for revenge, The Serpent’s Sin asks what you’d sacrifice for understanding.

I am now emotionally ruined, morally conflicted, and already counting the days until book three.

[Kaat SweetOnStories · Rating 4 out of 5]

She's herrrrrre: book 2 in Kathryn Ann Kingsley's Bloodlines series. Book 1 (The Serpent's Bride) was an absolutely wild ride. What I love most about it, is the relationship dynamic between central characters Raziel and Nadi, and so for book 2, I really wanted more fireworks between them. Well let me tell you - book 2 definitely starts with a literal bang. Holy crap, these two are just passion personified.

The Serpent's Sin seamlessly continues from where Bride left off, and it's wonderfully easy to roll back into the story. Raziel has just revealed he has found out the truth about who his wife really is. Rather than kill her on the spot - which is an Old Raz move - he sees and respects her for her insane shapeshifter skills, and, well... he's fallen head over heels in love with her. They make a deal sealed in a moment of mutual passion: she will help him take down his family once and for all. In order to do that, Nadi has to blend in as Monica once again, but with one important caveat: Monica isn't supposed to be human anymore, but a newly turned vampire. As both of Raziel's siblings attempt to woo "Monica"'s allegiance behind their brother's back, Nadi is forced to weigh the lesser of three evils: will she side with the man who killed her entire family, or with one of his two siblings - powerful Lana or kind Mael? One would say the choice is easy, but Raziel and Nadi are the very definition of the "it's complicated" relationship status. The only thing Nadi knows for certain, is that one in that family can be trusted. Not even the man she's falling in love with... and then there's the fact that she's still fae - any vampire's sworn enemy.

See? Wild. The Serpent's Bride oozed with foreboding, and in its sequel, the author really delivers with a plot packed full of twists and deceit and betrayal and all that good drama stuff. It's like she snatched all the things we love about a soap opera (twists, deceptions, betrayals, manipulations, stolen identities), but wrote it good. So good. With non-daytime spice. Like. Wow.

The Serpent's Bride heavily focused on getting Nadi situated within the Nostrom family and with Raziel, and The Serpent's Sin begins to lay bare how truly awful this family really is and how much Raziel is a victim of his circumstances. Because this second book focuses so much on these family dynamics and the impact of Raziel's formative years, I would have really liked to read more in Raziel's PoV... I think we had more chapters in his PoV in the first book. But I appreciate whatever we got, anyway. I love the insight a secondary PoV provides and we had that during some pivotal moments in the story. I am just really fascinated by Raziel. He's not your average MMC. He can be kind of a dick. He can be vicious. But damn if his love for Nadi doesn't turn me into a puddle of swoon.

This book is still very much enemies-to-lovers coded, because of the conflicting emotions and distrust both Raziel and Nadi experience, the latter especially. Nadi's feelings are all over the place: she doesn't even trust herself - though she's easy to see through. But they come together in a way that is everything I want from dark romance: it's a little bit tragic, it's very emotional, it's charged with an edging kind of tension and it's about embracing each other's deadly flaws. The ebb and flow of this relationship is sexy as hell, and it makes the moments when they do choose to trust each other a little more truly count.

The Serpent's Sin introduces readership to a second, rival vampire crime family: the Rosovs. This family's involvement in the story isn't one-dimensional: the relationship between both families are antagonistic on the one hand, and om the precipice of an alliance on the other. And even then, there's unpredictability everywhere. I'm loving how this book focuses on family feuding and intrigue. A few of our Nostrom family members are given more of a backstory and more complexity because of their history with the Rosovs and some shared plans for the future.

The one thing I couldn't get over, despite understanding that it's a detail and the plot needed to keep on going, was Nadi's skillset as a shapeshifter conveniently including her being what amounts to a careershifter. There is a sequence of events where she has to shapeshift into a few different personas several evenings in a row, each with different jobs and responsibilities, and we're supposed to suspend disbelief in order to accept that she has enough skill to blend in as a head chef. Nadi doesn't strike me as the kind of person who watches Masterchef, let alone someone who's ever cooked a day in her life. No. Just no. It took me out of the fantasy a little.

Apart from hoping for more of that explosive romance - which Kingsley definitely gave us - for book 2 I also hoped to see more fae involvement, and while we're not exactly there yet, we are gearing up to it, with some groundwork laid in Bloodlines' second installment. The second half of The Serpent's Sin is a doozie and has that true penultimate feel, like in a tv show: often it's the second to last episode where a lot of good, interesting, plot- or characterforward shit goes down and it's thrilling, making you excited for the finale. That anticipation setting in. The Serpent's Sin is very driven and confident: upon finishing there's the sense that everything is going to fit together beautifully for the series' conclusion. I'm chuffed about the direction Bloodlines takes from here on out, and my grabby little hands will not ease up until book 3 is in them.

**Thank you NetGalley and Second Sky for generously providing me with a copy of this book; all opinions expressed are honest, voluntary and 100% my own.**

----------
well, that was one hell of a ride. excited for book 3!

[Sammi · Rating 4 out of 5]

✨ARC✨

Oh I need book three right now!
I love these two characters and I need to know how it ends!

The tension, the danger, the spice!
Trust no one and risk everything.

I do wish I'd been able to listen to the audio of book two as I really enjoyed the narrators from book one, but the story itself is so good! I couldn't put it down!

I can't get enough of these two!

Thank you to Second Sky for the advanced copy.

[Jane Rush · Rating 1 out of 5]

Not for me

DNF. I read the 1st book and found it not too bad. This one is not! Very poor editing with repeated inconsistencies.
1. Told FMC is barefoot as she lost her shoes, 10 pgs later, she stomps on the vampires foot with her stilettos
2. Shapeshifted to a 6ft+ male with clothes but 6 pgs later told her underwear was shredded from when she changed from human to fae
3. Straight into restraining neck with belt for explicit sex on altar

No, I'm not a prude, but would appreciate some decent writing leading up to this action and feel the need to point out all this happened by page 20!!!

[Faeofashandpayne · Rating 5 out of 5]

The Serpent’s Sin by Kathryn Ann Kingsley 🖤🐍

Omg… the way I absolutely adore Raziel & Nadi and their twisted, broken, beautifully messed-up relationship even more after this book?? I’m feral. If I could sum it up in a few words: trust no one & deliciously deviant spice.

This book had me on edge every single chapter — constantly second-guessing what would happen next. I truly didn’t know which way things would turn, and I was not disappointed.

The rage I felt on behalf of Raziel in this one? Mighty. If I could be a fae-mermaid assassin, I’d be out there taking down half these monsters myself. 😤

Each book just keeps raising the stakes and leaving me gasping for more, and I’m so excited to see where this story goes next.

✨ 5 stars and even more obsessed with this dark, addictive enemies-to-lovers masterpiece. ✨

[Zoé-Lee O'Farrell · Rating 5 out of 5]

So we're back with Book Two, and you know it's going to be a good one when the opening chapters are full of a lot of spice!! I had to be careful that I didn't have the noise on too loud on my audiobook, and my headphones were permanently in, just so that the mini one didn't hear it, because I was not expecting all of that straight away!

This was a book mainly of navigation between two characters, following the deal they made at the end of book one. This book completely follows it straight after, and we deal with Nadi and Raziel and how they are going to navigate in a world where Nadi should be dead! Also, his family want her dead!

There are power plays, very much like a mafia. I love that Nadi and Raziel fall in love!! Although it's going to be interesting to see what happens now that at the end of this one. I cannot wait to see where we go, because, Jesus, this is gonna be mental.

I'm excited to see where we go from here, because I just don't know. We're going to watch them navigate into something different, in a new place. And it's, I think it's gonna be explosive. We've lived in Raziel's world for quite a long time, and now we're gonna live in Nadi's world. And yeah, looking forward to seeing how this one blows up.

One thing I will say is that I was listening to the audiobook. I say, listen, I devoured it in one day. Some of the names are quite similar, so I did kind of lose track of who was who, but I don't think I would have done so had I read the book.

So you do have to kind of be more on the ball, because some of the names sound the same, but that's just me. That's not the book. That's not a moan.

I love this series. I think it's fantastic, and I, yeah, just love it. Absolutely love it.

[Madison · Rating 4 out of 5]

4 - On the edge of my seat



WHAT TO EXPECT:
✨ hidden identity
✨ vampires, fae, humans
✨ arranged marriage
✨ unlikely alliance
✨ hypnosis gifted
✨it's like succession but with vampires and murder
✨ headstrong fmc
✨ spice
✨ 3rd act twist


Quick Thoughts:

I thought this was a duet, not a series so by 90% I was freaking out. This book makes you feel uncomfortably tense like a thriller, and I loved it. I was CHEERING for my girl Nadi.

I loved:

Plot
The main plot is Nadi is going to help Raz kill his entire family, yet Nadi can't trust Raz. It's so twisty and turning, I was not sure who Nadi should trust the entire time. I was obsessed with this plot line because I felt chaos the entire book.


FMC
Due to the fact she goes by two names in this I labeled this as FMC. Nadi/Monica was incredibly fun to follow. She's an assassin and she doesn't pretend she knows everything. She fully expects to die for her cause, and because of that she's fully dedicated to doing whatever she needs to do to fit the role. I absolutely love the thoughts in her head as she's pretending with Raziel’s family. She wanted to betray everyone, and honestly I think the ending made sense.

The Ending
My god. The last 20% of this book was a ROLLERCOASTER. I was gasping, and in shock. I don't want to spoil anything, but wow did this make the book.



The thing I disliked
Relationship focus
This book really focused on the plot and the dynamics of the family. I did need more strength in Nadi and her relationship with Raz. I felt she could align with anyone basically, and I wanted more pull for Raz.

Overall, I enjoy this story! I cannot wait to read the next one!




ARC review

[Faye · Rating 5 out of 5]

This is book 2 of the Bloodlines series and boy oh boy!
Kathryn weaves such a delicate blend of danger and love that made my heart race in so many different ways. The spice, the drama, the deceit, the lies and the danger is so well crafted once again I couldn’t put the book down and devoured in 48 hours. It would have been 24 hours if I didn’t have to adult 🤣

The relationship between Raziel and Nadi is intense throughout, I’d didn’t think it could get more intense than book 1, I underestimated Kathryn’s sheer ability to gripe her readers and keep them pinned in place begging for more!

Expect more lust, more violence, more spice, more lies, more family dramas, more suspense and more paranormal tension!

Can vampires and the Fae find harmony?
I love that not only do we have some serious dark romance but we also have a story bordering on horror with the tension of revenge and the gore of the violence. Kathryn’s descriptive writing makes you feel right there and vividly brings these scenes to life. Everything is so magically woven and flows so naturally that you feel right there seeing everything unfold before your very eyes.
The ending was totally unexpected and didn’t see it coming, but I love the set up for book 3 and am really excited to see where it goes from here. It was a place I never thought Nadi and Raziel would ever end up!

Will anyone get their revenge?
Will Razeil and Nadi ever be truly honest with each other?

[Kourtney Delair · Rating 4 out of 5]

•• “𝘕𝘢𝘥𝘪… 𝘐 𝘣𝘦𝘭𝘪𝘦𝘷𝘦 𝘺𝘰𝘶’𝘭𝘭 𝘨𝘦𝘵 𝘺𝘰𝘶𝘳 𝘸𝘪𝘴𝘩. 𝘉𝘦𝘤𝘢𝘶𝘴𝘦 𝘰𝘯𝘦 𝘸𝘢𝘺 𝘰𝘳 𝘢𝘯𝘰𝘵𝘩𝘦𝘳? 𝘠𝘰𝘶’𝘭𝘭 𝘣𝘦 𝘵𝘩𝘦 𝘥𝘦𝘢𝘵𝘩 𝘰𝘧 𝘮𝘦”

After that shocking ending of The Serpent’s Bride, I was very happy this picked up exactly where we left off in the first book. The true enemies to lovers theme stays strong throughout this installment, despite the connection our characters so obviously feel.

I did really appreciate that this focused on the struggle of truly developing feelings for a real enemy and all the complexities that come with it. But, it did seem that Nadi was the only one fighting the connection she had with Raziel, and I did find it made her character a little frustrating at times. In the end though, she came through and made the choices I hoped she would - even though they went against everything she thought she stood for.

•• “𝘓𝘦𝘵 𝘪𝘵 𝘨𝘰. 𝘍𝘦𝘦𝘭 𝘪𝘵 𝘢𝘭𝘭. 𝘌𝘷𝘦𝘳𝘺𝘵𝘩𝘪𝘯𝘨. 𝘛𝘰𝘯𝘪𝘨𝘩𝘵, 𝘸𝘦 𝘣𝘳𝘦𝘢𝘬 𝘪𝘵 𝘢𝘭𝘭 𝘥𝘰𝘸𝘯… 𝘢𝘯𝘥 𝘴𝘦𝘦 𝘸𝘩𝘢𝘵’𝘴 𝘭𝘦𝘧𝘵 𝘸𝘩𝘦𝘯 𝘸𝘦’𝘳𝘦 𝘥𝘰𝘯𝘦”

This really focused on the intricacies of falling for something you’re not meant to love and stayed extremely realistic the entire time. That being said, I’m a romantic at heart and wanted a little more spark between our mc’s instead of them fighting their feelings so hard. They seemed to have more tension in the first book and I wasn’t quite as invested in this one because of it. Now that the lines have been drawn and the choices have been made, I do think the next book will give more swoon worthy moments with our mc’s.

[Olivia · Rating 5 out of 5]

Okay, I really liked The Serpent’s Bride, but this was such a great way to follow up the first book. I really loved it! This one begins right where book one ended and I loved that! There was no time jump, so I didn’t have to worry about trying to catch up or try to figure out what happened during that time.

I loved Nadi in the last book and I loved her even more in this one. We get to see her struggle with her true feelings for Raziel and we get to read more about her family and people as she contemplates what her next steps should be. I loved the agreement that she had with Raziel and how she got to be herself with him. She gets proposals from his siblings to turn on him and I absolutely loved her decision, which leaves us on a cliffhanger for book three.

In this book, we get more of Raziel’s past. It was heartbreaking learning about what his awful mother put him through, but I loved how Nadi got revenge on his behalf. He, like Nadi, struggles with his feelings for her. He also knew his siblings had a love/hate relationship with him, however, he learned the extent of their hate. I loved how protective he was of Nadi, but he also understood her wanting to get revenge for what he did to her family all those years ago.

Overall, I truly loved this book. It went by so quickly and there were so many things that I didn’t expect. I loved the cliffhanger too! I cannot wait for book three and if you love vampire x fae, enemies to lovers, spicy, romantasy, this book is for you! I would definitely recommend this series.

Thank you Kathryn Ann Kingsley, Second Sky and NetGalley for the ARC for an honest review.

[A Court of Words and Letters · Rating 5 out of 5]

Brutally dark and seductively perilous and quick reads that will keep you hooked from start to finish.

Kathrynn has done it again. The Serpent's Sin takes all the good elements of The Serpent's Bride and absolutely smashes them out the park for the second book. Everything about this story is dangerous, sexy and dangerously sexy. The melding of the mafia style family from dark contemporary romance with vampires, fae and other-world fantasy elements is so perfectly blended and I absolutely ate it up.

Raziel Nostrom - WOOF. Everything about this character is so complex, and layered and I LOVED getting to see a bit more of his past in this book. Did I mention WOOF?! How is a man this cruel, this HOT. Good grief.

Nadi - Oh Nadi. There were a few moments where I was SCREAMING at her to make better choices, but in all honesty, I completely understand why nothing is easy when it comes to the decisions she has to make. Everything has fallen apart around her, there is a delicious cat and mouse game she finds herself and Raziel playing together, but it does seem as if they are not the only players, and their mutual desctruction is not the only game.

The Nostrom's are DYSFUNCTIONAL and I LOVE IT. There is nothing redeeming, truly, about Volencia, Lana, Mael or any other member of Raziel's family, they are all out to win, and they will step on fae, humans and the other vampire families along the way.

The stakes are much higher in Book 2, and when you thought Book 1 had you understanding motives, let Book 2 completely sideline you in the BEST way. We've got some severe generational family trauma, a chess game being played (when everyone else is playing chequers) and some many small intricate webs being woven, it's hard to tell who the real prey is.

I am FERALLY awaiting book 3, that ending was INSANITY.

[Mads · Rating 4 out of 5]

Big, big fan of these vampire/fae books. This is how you do enemies to lovers!!! This right here!!

Things I love:
🐍Crazy vampire mafia-esque family
🐍Deadly shapeshifter fae assassin
🐍They hate that they love each other!!!
🐍His family is terrible but in a juicy way
🐍Lilivra serves diva
🐍Their relationship is so broken and messed up yet it's so, soooo juicy. This series is so addicting at times

The only thing that took away points for me was that I felt like we kind of went in circles in the middle so it lagged at times. I could have used those words to dive a little deeper into the siblings and their motivations, or even just get more romance between Raziel and Nadi. However, the book is so short that it only really took half a star off for me, and I'm still really excited for the next (maybe last? I'm unsure) book.

𝑻𝒉𝒂𝒏𝒌 𝒚𝒐𝒖 𝒕𝒐 𝒕𝒉𝒆 𝒑𝒖𝒃𝒍𝒊𝒔𝒉𝒆𝒓, 𝒂𝒖𝒕𝒉𝒐𝒓, 𝒂𝒏𝒅 𝑵𝒆𝒕𝒈𝒂𝒍𝒍𝒆𝒚 𝒇𝒐𝒓 𝒈𝒊𝒗𝒊𝒏𝒈 𝒎𝒆 𝒕𝒉𝒊𝒔 𝑨𝑹𝑪 𝒊𝒏 𝒆𝒙𝒄𝒉𝒂𝒏𝒈𝒆 𝒇𝒐𝒓 𝒎𝒚 𝒉𝒐𝒏𝒆𝒔𝒕 𝒓𝒆𝒗𝒊𝒆𝒘. 𝑨𝒍𝒍 𝒐𝒑𝒊𝒏𝒊𝒐𝒏𝒔 𝒂𝒓𝒆 𝒎𝒚 𝒐𝒘𝒏 ✮⋆˙

[Faye Anne · Rating 5 out of 5]

The Serpent's Sin is book 2 of the Bloodlines series. Book 1, The Serpent's Bride, had a dramatic ending, and book 2 picks up directly from there. I really liked book 1, but I LOVED book 2! There was never a dull moment in The Serpent's Sin - it really did take everything great about book 1 and build on it. The plot, the character development and the romance were all even better because everything was set up so well in The Serpent's Bride. 

This is TRUE enemies to lovers, in a brutal world of vampires vs fae, with power battles between the vampire clans, and even in-fighting within each clan too. This means that there's lots of twists and turns, potential betrayals and possible allegiances to be made. The enemies to lovers romance is perfectly done and there's a perfect balance of plot to romance/spice. I just can't wait to see what happens in book 3!

Disclaimer: I received an Advance Reader Copy from NetGalley but this is my voluntary and honest review.

[The Bookish Damsel · Rating 5 out of 5]

4.5 stars

Why am I so addicted to this series? I can’t get enough of Raziel and Nadi, and I’m absolutely thrilled that we’re getting a third instalment in their journey. This book took a turn towards the end that I truly did not see coming. I was completely convinced Raziel and Nadi had everything figured out - only to learn they absolutely did not.

Mael and Lana really revealed their true colours this time. I still don’t like them, but I have no doubt Raz and Nadi will eventually get their well-earned revenge. On the bright side, ding dong, the witch is dead! Volencia, the cruel and evil matriarch, finally met her end at Nadi’s hands, and honestly, it felt long overdue. After everything she did to Raziel, it was satisfying to see justice delivered. Let’s rejoice at that!

What I’m most eager for now is Nadi finally confessing her love for Raziel. Book 3 is going to be very interesting, and I cannot wait to see where their story goes next.

[Amanda P · Rating 4 out of 5]

As addictive and twisty as book 1!!

After the ending of book 1, I could not wait to get stuck in with this book, and was very grateful for an early copy 🫶

Serpent’s Sin is just as addictive, and sexy, and twisty as book 1. It was the wild ride that I needed to get me out of a bit of a slump!

What I loved:

🐍 It was so sexy. The start especially, was a right little treat, with a bit of edging 😈 And I loved how there started to be softer and more intimate moments between Raziel and Nadi as well! Especially his forehead kisses 🥰

🩸All the betrayal and mistrust. I honestly still don’t entirely know who we can trust and who is genuine in this world, which is fun! There’s so many moving parts and people with different alliances, the book really keeps you on your toes.

🐍 The relationship development. I loved seeing Nadi and Raziel become closer, especially her dealing with all her conflicting feelings. And seeing more of his background, truly broke my heart. Deep down Raziel is such a broken boy.

All in all, a fun read and I can’t wait for book 3!

[Nancy Weiler · Rating 4 out of 5]

Wow, what a sequel and so unexpected in the directions I thought it was going. Absolute must read.

I loved that we got more of their relationship and steamy is an understatement. I was absolutely here for it. The way the second book focuses more on Raz had me swooning, and feeling so much more empathy for his character. We discovered more of the fae sirens and of course Kathryn leaves it on a cliffhanger which makes me yearning even more for the next.

What I absolutely love the most about the bloodlines books are they’re super easy to get into, without heavy world building and a really easy yet powerful plot which keeps you so intrigued in the storyline. Vampires and spice basically go hand in hand in my opinion and Kathryn writes it so well.

Things I loved

ENEMIES TO LOVERS
REVENGE / BETRAYAL
DARK VAMPIRE ROMANTASY
MARRIAGE OF CONVENIENCE
SPICE 🌶️🌶️🌶️

Thank you so much Second Sky for the review copy.

[Katelyn C · Rating 4 out of 5]

4/5 Stars

ARC Review - Releases January 23rd

Are you looking for an original, plot heavy vampire romantasy? The bloodlines series has it all! This is the second chapter in a steamy, enemies to lovers story with a strong political plot. I appreciated that this is more than just your typical smutty vampire series. This stands out as far as original plot goes, with a fae/mermaid shifter FMC and a morally black MMC who is a part of a mafia-like vampire family. I enjoyed this second book more than the first, I found the plot to really expand and I had no idea what to expect. I actually would have liked to see a bit more spice & romance, but with another book coming, I anticipate to see the love grow between the main characters.

What to expect in The Serpent's Sin:
~Enemies to Lovers
~Fae & Vampires
~Mafia Family
~Assassin FMC
~Morally Black MMC

[mila_readss · Rating 5 out of 5]

˖°❀⋆.ೃ࿔*:･ . 𝗧𝗵𝗲 𝗦𝗲𝗿𝗽𝗲𝗻𝘁'𝘀 𝗦𝗶𝗻 ˖°❀⋆.ೃ࿔*:･ .

𝗚𝗲𝗻𝗿𝗲: Dark Fantasy Romance 
𝗟𝗲𝗻𝗴𝘁𝗵: 334 pages
𝗢𝘃𝗲𝗿𝗮𝗹𝗹 𝗿𝗮𝘁𝗶𝗻𝗴: 5 ⭐ 

• Enemies to lovers 
• Spicy scenes 
• Vampire x Fae
• Morally grey MMC
• Badass FMC
• Shape shifting 
• Hate to love

I was really looking forward to this, and I'm so happy I got to read it early. 

Being back in this world made me so happy. Watching our serpent gradually become obsessed, and fall in love was everything, and the ending!? Once again, it left me craving so much more! I need the third book like, right now! 😭

There was a ton of plotting, revenge, betrayal, action, and some interesting family dynamics lol, plus the spice was written just right. It truly captured all the emotions they felt for each other.

If you're on the hunt for a fast-paced, spicy, and addictive new fantasy series with a hate-to-love dynamic, then this is definitely for you. I promise you'll have a blast!

[Shannai · Rating 5 out of 5]

5 ⭐️

Thank you to Noelle and the entire team at Second Sky books and NetGalley for the review copy of The Serpent’s Sin. All opinions expressed in this review are entirely my own.

Incredible and action-packed, this book had me holding my breath right up until the very last page, once again! Kathryn truly knows how to write an addictive paranormal romance that hooks you from start to finish, because I was unable to put this down!!

Every scene is charged with tension, emotion, and an unsettling feeling of danger around the corner!

Raziel is a weaponised monster, yet somehow I found myself feeling deeply sorry for him. He’s the most feared vampire, nicknamed the Serpent, but beneath that brutal exterior lies a character who’s been outshined, ostracised, and manipulated by his own family, shaped into a weaponised tool, which Nadi is still understandably conflicted about. Kathryn does such an incredible job of peeling back his layers, showing the pain and loneliness behind the power, and likewise with Nadi, how she grapples with her own grief and as she is now in a predicament where she’s working with the monster that murdered her family.

And then there are Kathryn’s cliffhangers, utterly ruthless in the best way. She has this talent for leaving you reeling, teary-eyed, and desperate for the next book. I was so close to tears by the end, torn between awe and heartbreak. I’m beyond excited for what’s to come and can’t wait to see where book three takes these characters.


Pre-read October 2025: need a lil pnr fix this spooky season, and I’m so giddy to read about these two!!

[BookedWithCara · Rating 4 out of 5]

This second book on the Bloodlines series picks off exactly where book one ends, which I loved. The story was so fast paced—under 400 pages and so much happens! I loved seeing more side characters and more of the inner mafia working. the world felt expanded and all the problems facing our main characters in book one became even more complicit. There were so many twists and so much deception that I wasn’t sure how our main characters were going to come out at the other side. And that ending? The next book is going to be more wild. Honestly, I need to see what happens to the characters.

Thank you to Second Sky for my arc. All opinions are my own.
3.75⭐️ rounded up

[Sam ✨️ Justamumandabook · Rating 5 out of 5]

6☆ I ate this book up and left no crumbs! I need 3-5 business days to process what I have just read. I dont think my review will ever do it justice.

This book made me feel! I never expected to cry, but my goodness did Raziel make me feel all the emotions. Nadi, I cheered on, she is the epitome of a strong female. I got whiplash and vertigo from teying to guess who was manipulating who and who who was telling the truth.

I cannot wait to see where Book 3 goes. Kathryn, please let them have the happy ever after they deserve 🥹

Thank you Second Sky, Kathryn and Noelle for sending me an earc to review.