Jump to ratings and reviews
Rate this book

Emperor's Assassin #4

Dragon Blood Curse

Rate this book
The generals that once served Emperor Tallu now pursue us across the continent. We have one chance to save our lives, one hope at a future that we both so desperately want. With new allies and old nemeses, we have to risk our lives to create a world for our love.

379 pages, Kindle Edition

Published March 16, 2026

Loading...
Loading...

About the author

Kai Butler

26 books620 followers
Kai has been reading and writing romance novels since she was a teenager. She lives in California with her two children and her very supportive husband.

She writes M/M romance with an emphasis on HEAs and all the feels. Her current series are San Amaro Investigations and the Imperial Space Regency Novels. She likes dashing heroes and couples with banter.

Ratings & Reviews

What do you think?
Rate this book

Friends & Following

Create a free account to discover what your friends think of this book!

Community Reviews

5 stars
245 (46%)
4 stars
205 (39%)
3 stars
62 (11%)
2 stars
9 (1%)
1 star
1 (<1%)
Displaying 1 - 30 of 58 reviews
Profile Image for Alexia.
491 reviews
April 7, 2026
I debated extensively with myself about what rating to assign to this book, and even now, I remain uncertain. I genuinely enjoy this series and I give high ratings to all its installments, yet there was always something holding it back from becoming a personal favorite. Until this book, I couldn't quite identify what that was.

Now I understand, it's the side characters.

Let's start with the world-building, as the author has crafted an intricate and richly layered universe. The depth and detail are so impressive that it feels as though one could flip open a history book and learn everything about this world. Each installment expands on the lore, revealing the customs, traditions, and histories of numerous nations, illustrating their rises and falls across the ages.

Next, the political intrigue deserves special mention for its masterful execution. The complexity of the schemes, the multiple levels of deception, and shifting alliances create a narrative so sophisticated that it closely mirrors real-life politics. The author’s skill in portraying such layered, realistic political maneuvering is truly commendable, and it consistently keeps me engaged and eager to see how conflicts unfold.

Having discussed what I most adore about this series, I must also confess what frustrates me so profoundly, namely, the side characters. They are overwhelmingly obnoxious and irritating, often stepping on my nerves and provoking tears of frustration. There have been moments when I harbored such strong feelings of disdain that I would have gladly seen them meet a cruel fate, and I wouldn’t have been upset. It’s not that they are bad or good, but their actions drive me to scream at my book in exasperation. These characters are neither stupid nor simple, in fact, they are layered, well-developed, and have backstories that justify their motives. Yet, their complexities only deepen my annoyance and dislike.

Getting that off my chest, I can now turn to my favorites, Airón and Tallu. Despite some moments of annoyance, I truly love them. Airón is a protagonist who may not win everyone’s admiration. His assassination skills are flawed, and he often makes poor decisions. However, his growth over the course of these four books transforms him into a character who commands respect. His evolution, fraught with mistakes and lessons, makes him more relatable.

Tallu is the archetype of the tortured love interest, eager to distance himself from his heinous family and their sins. What sets him apart is the way he is written, which doesn’t evoke overwhelming pity or frustration but instead inspires genuine love. His desire to dismantle the corrupt foundation his family built(regardless of personal cost)paints him as a deeply layered and complex character. He genuinely wishes to see justice served, even if it means destroying himself in the process.

Their relationship, although primarily a subplot within the larger narrative, is profoundly touching whenever depicted. Their mutual love and unwavering commitment to each other are palpable. They care so deeply that they would risk everything, including their own lives, to protect the other. Their tenderness, communication, and the strength they find in each other exemplify what true love should be: not a source of pain but a source of empowerment.

In conclusion, the way this book ended has left me eagerly awaiting the next installment, book five. Despite my hatred for the side characters, Airón and Tallu constantly rescue this series for me, reaffirming my dedication and excitement to see how their stories continue to unfold.
Profile Image for Eugenia.
2,006 reviews333 followers
July 21, 2026
This series!!! So freaking great!!
I binged the first 4 this weekend ❤️❤️❤️❤️❤️🙌
And now I have to wait until October for the next one 🤯
Profile Image for Jinx.
259 reviews54 followers
May 9, 2026
I feel like the author has really lost the plot of this series for the sole purpose of stretching it out. This book dragged so bad. It was page after page of nothingness. There was no forward movement to the story at all. I also felt this disconnect with Airón and Tallu. They spent a lot of chapters apart where Airón would risk his life and wellbeing all in the name of saving Tallu but the sacrifices never seemed to go anywhere. It was just one reckless decision after the other with no successful outcome and that at the end of the day moved the story nowhere. The only thing to come out of this book was a new cast of side characters that don’t feel important to the plot but also feel like a red-herring. Cos why would the author introduce them unless they were expendable or a last minute plot-twist villain? These books have gone from my most anticipated read to not knowing if I’m gong to continue reading this series.
Profile Image for Mimi.
34 reviews
Read
March 26, 2026
I think I might be getting tired of this series bc I gobbled up the previous books but am having a hard time with this one.

The plot picks up with immediate action right from where the last book left off and it felt very disconcerting. There was no break to gather my bearings, you’re immediately thrust into all the intrigue. I read the last book only a few months ago, and still felt very lost. I fear that folks who haven’t read the last book immediately before this are going to have a hard time.

It also feels like the romance has taken a complete backseat to the plot. This wouldn’t be as much of a problem if we got other POVs, but bc we only get one MC’s POV, so this epic plot and world building starts feeling very narrow and constricted.

I prefer Hailey Turner’s approach to the Infernal War series than the way this series is evolving. It’s too many books from only one character’s POV for such a epic heavy plot and it’s all feeling very chosen one focused bc of that. Hence why I’m having a really hard time with my rating even tho I really enjoyed the previous books.
Profile Image for Elisa.
356 reviews270 followers
August 3, 2026
I think this is the second to last book in this series, but unfortunately I think it might be the last one for me.

I had been enjoying this series and had fully planned on finishing it; however it feels a bit like the series had been planned as a trilogy and then was expanded half-way through, because the pace and narrative structure of the third and fourth books is really quite different from the first two.

The first two books were very well structured, with an overall storyline that managed to include some surprise reveals while also developing in a way that felt very organic and allowed everything to gradually progress and come together; at the same time, the world building was woven into the narration quite smoothly so we gradually got to know the characters and understand the world, without any major info-dumping. Those first two volumes in the series were well thought-out and I found them gripping and hard to put down, even if they were not fast paced per se — the rhythm and progression perfectly suited the story.

Book three departed from that and it felt, if not quite directionless, definitely like the story was meandering a bit, like someone taking the long way around to get to their destination, and occasionally getting a bit lost in the process.

This issue was unfortunately present in this fourth book as well; and while I enjoyed getting to know another culture in the empire, I didn’t feel like there was quite enough story progression or character development for a whole book. To be honest, most of it felt like filler, like the ending is purposely being put off.

I get the idea behind these two books, and why they are separate: we get to visit different parts of the empire and the world the story is set in, and there are slightly different conflicts (though both playing into one larger one) but unfortunately I didn’t feel like there just was enough substance to either book.

It’s really a pity because the first two books were SO good, and I really like the main characters, their journey, and the world as a whole; but the way the story has gone, I feel like I have largely lost my connection to them so I’m not engaged enough to need to finish the series.

So I’m giving this 3 STARS — it’s not bad, but it’s not really particularly memorable or impactful as a whole, either.
Profile Image for Kristine.
3,730 reviews58 followers
April 13, 2026
4.25 Stars ⭐️

I have really enjoyed this series and have fallen in love with both Prince Airón and Emperor Tallu. In this book, the two of them are dealing with the mutiny from their two Generals and are trying to come up with alternate strategies.

They end up taking a route by water that doesn't exactly turn out the way they had planned. In the meantime, there are discoveries being made about what exactly is going on at some of the other areas - elven areas that are yielding some major surprises.

This book felt a little slower than the previous books, but it still did move the overall storyline forward. Tallu now has his younger brother and Heir with them, along with the former Emperess but he is not completely convinced of her loyalties.

As usual, this book did give us just enough to have some major information uncovered, but unfortunately, it left us with more questions than answers.

It looks like I will again be eagerly awaiting the next installment :)
3,053 reviews3 followers
March 17, 2026
exciting, entertaining read

Rating: 4.5🌈

Dragon Blood Curse was an exciting, immersive experience all around, as Butler’s penultimate story brings more mythical characters and magical regions into play with this fantasy action adventure.

Prince Airón and King Tallu have multiple schemes at work and not all are going according to their intended intentions. With their enemies bringing larger powers and armies against them, Airón and Tallu race to find a cure for the deadly curse that affects both brothers. And their own council falls into chaos and loyalties are divided as the enemy attacks.

It’s high politics, subterfuge, magical terrorists, and wars between enemies being waged across their borders and territories, and everything and everyone suffering.

Of course, there’s a prophecy or two, sacrifices that figures mightily in the coming novel, angst and some really great layering of information and people (look to the North) that just ups the stakes here.

No spoilers but this just grabs the reader from start to finish. For me, the relationship between Airón and Tallu is the least compelling element here. So many other great aspects of the series and story to focus on.

Great job. And I love the Spider. Awesome.

Cover by Hannah Latham at oexasart Lettering by Laura at Covers by Aura

Emperor's Assassin (5 book series)
Betrothed to the Emperor #1
Emperor's Wrath #2
Shadow Throne King #3
Dragon Blood Curse #4
Crown of Ash #5 - Oct 26,2026
Profile Image for Ailyne.
236 reviews50 followers
March 20, 2026
Im really going to need my boys to have a HEA because I AM TIRED!
Profile Image for maqready.
5 reviews
April 3, 2026
this book is my favorite of the series so far.
the tragedy and ruin brought to Tavornai and its people by the evil genocidal empire hit too close to home, unfortunately, i could barely hold back tears at times. and it's gonna be even worse going further to other conquered lands 💔
and yet i can't wait for the next book.
.
.
.
.
ps. Kennelmaster, pls live, im begging you.
Profile Image for Lila.
1,021 reviews195 followers
June 20, 2026
I just keep getting more invested in this series.

There's definitly a clear progress in terms of the writing skill throughout the series. I admit, the first couple of books I loved, but I also noted that the writing and the editing could have been better. This is not perfect, but it's definitely getting better.

Honestly, I'm torn between wanting to see the end of the series (and what happens to Tallu and Airon) and it never ending because I want to see more of them.
Profile Image for Nela.
51 reviews
May 29, 2026
The plot is getting a bit complicated and seems to be losing focus but learning another bit of lore and another type of magic and the cost of wielding it was interesting enough to keep that 4th star. I am assuming though that the next book is now the last? I'm not sure this series will hold my interest forever so I'd actually be happy if we'd get a satisfying 5th and final book.
Profile Image for ari ✦.
83 reviews10 followers
August 11, 2026
this book is definitely less action-packed than the previous ones but i loved it just as much. i can’t wait to return to this world when the next book comes out!
Profile Image for I Baron.
33 reviews
May 6, 2026
Well that escalated, as they say! Still irritating in parts where the author seems to forget about characters, characters forget about abilities, or brand new information that was never presaged changes everything (maybe realistic but not very satisfying jn a book). On the whole- I’m invested and the characters really need to adapt to their original goals being superseded by events.
Profile Image for Florian.
93 reviews
Read
April 30, 2026
YES!

I'm so invested, I really really hope Kai Butler doesn't stop writing the Emperor's Assassin saga at least for another four books. (Please and thank you.)

I had such a visceral reaction to some parts with the maritime horrors I haven't experienced since The Odyssey. And in a way, it was a modern Odyssey, really. Especially considering Airón's emotional journey: Absolutely brilliant!

The first books are good too, but I feel like the series gets exponentially better and better with each new turn, while the style stays consistent. It's bloody marvellous! Little things I was hoping would happen, happened, new fascinating things were revealed, this could easily go on for a long time, there's so much potential.

Some side characters honestly deserve their own books.
Sagam, of course. He had always been interesting, and he's just became even more so.
But also Lord Chaliko! I want to know the man.
Also also Homisu! We barely know this guy, but I love him. His keen expertise, kind heart and that sword strapped to his waist...like, who are you?

Some of my personal highlights:
• "I have to appreciate how you never bring us easy problems, General Saxu." This line was so cliché but so awesome. Very old-school adventure film line, very cool.
•Loved that the soldiers got the real side of Airón in that little night swim. It could potentially lead to great things in the future.




• I just love horny Tallu. That's it.

Now some things that made me frown:
• Prince Hallu is less than four years old, even if he's raised as the future emperor, he would not speak like that AND most definitely wouldn't ask THAT. I do suspend my disbelief, believe me, but that's just a no. Maybe a very mature seven-year-old, raised by mind games and court gossip, but not an almost toddler. (Unless there's a magical explanation.)





• This did not make me frown, but I dearly wish for a timeline with all the Emperors of House Atobe and their rules in addition to the map. That would be useful.
Profile Image for Ariana  (mostly offline).
1,721 reviews113 followers
May 3, 2026
3,5 stars

I started this book 3 times, abandoning it twice because there is so much political talk and intrigue in the first 20 to 30%. And virtually no Tallu and Airon.

I persevered the last time and things do get better later on. I’ll not lie, I found the very much action (rather than romance) based plot a bit too much for me. (Tbh, I know this is the author’s style, so I shouldn’t complain.)

However, I always struggle with a huge amount of names and characters. Once I decided not to worry about that and accepted that I didn’t necessarily need to know or remember every single person mentioned and to understand every political decision to get the gist of things, reading felt a bit lighter.

Tallu and Airon are trying to find Spider in this book because they believe that this animalia can help Tallu beat his curse. I enjoyed that treacherous journey and all it entails.
Interesting that Airon seems to accumulate a lot different magic along the way which surely, ultimately, will lead to a point where he needs to use it.
I also liked the whole philosophy surrounding the elder trees which reminded me of the San Amaro series by this author. There’s clearly a very strong message here I wholly approve of.

Tbh, my main problem with this series is that I still can’t fully connect with Airon.
He still irritates me. In things he says or does or thinks (we are in his POV only). There is this certain arrogance, this vibe of ‘know it all’ that makes me want to shake him. But it isn’t that alone, and while I really can’t put my finger on my issue with him exactly, I guess it simply comes down to me not gelling with him. Sigh.

But, I guess I will be back anyway to see where the next book takes Tallu and Airon.
Profile Image for Dalegendaryreader.
880 reviews23 followers
March 20, 2026
“I want you. I want a life with you. That is not possible as long as the Imperium survives.”

The generals that once served Emperor Tallu have the Imperium and declared war. Emperor Tallu and Prince Consort Airón have to find new allies at the same time embark on a secret journey to save their lives.

Started reading this during release day because ya girl couldn't wait but I also saw the next book gonna be published this October so I debated whether to binge-read this or savor. I chose savoring the book.

Ngl, the reason why this was not a 5-star book was because of all the travel. I get it, it's a fantasy book and they have to travel but dang, I don't really like the travel aspect in books. Not the book's fault, but it's me.

“Tallu, I cannot save you if I lose you first.”

I love how much more high stakes we are. Every book and in every journey is one step closer to Emperor Tallu and Prince Consort Airón's end goal. I love it sm! The adventure, the way the politics works, it was amazing on how the author wove together the story. You can see there's a way and that everything is a stepping stone.

“It is better when you are with me.”

The romance sprinkled in here was so endearing. We know what are at stakes and yet we can definitely see how fiercely Tallu and Airón loves one another.

I cannot wait for October please.


Profile Image for Kimber.
Author 10 books3 followers
May 22, 2026
This series, this book...

I have no adequate words.

I have been pulled into this series heart and soul, totally unable to stop reading, except for living life and doing necessary things, of course. I didn't leave comments on the others, though I will probably fix that when I can, because I was so eager to go to the next.

I absolutely recommend this book to anyone who is a fan of fantasy, adventure, romance, and vast emotions tied around amazing world building and characterizations. This was more than just a book to me, it was art, brilliance in action, and it's made me think in different ways than I normally have before reading this series. I know that sounds immensely larger than just a simple story, and maybe it's something to do with just me, but I cannot recommend this series or this book enough. This author has done wondrous things with these words and made these characters come alive for me in a way I didn't expect. I can't stand the wait till the next one comes out, but I'm going to have to.

I wish I could thank Kai Butler personally, but I'd probably seem like a weirdo stalker anyway, so best not go that direction. ;p

Bottom line? If you're looking at reviews and comments, then you're definitely considering this book. Do it. I cannot imagine you will regret it.
Profile Image for SNik.
834 reviews22 followers
Review of advance copy received from Author
March 13, 2026
Fourth in series (Emperor’s Assassin), must be read in order. Fantasy. Established couple. Found family. Single POV.

Immediately following book 3, Airón and Tallu remain intent on tearing apart the empire, however they are racing against time as they are pursued by the traitor generals and trying to find a way to end Tallu’s blood curse.

Since Airón and Tallu are solidly in love and committed to each other in all ways, this story hits harder with Airón’s desperation to save Tallu. The journey across the empire still has them deep in political intrigue and trying to survive as they juggle the outward appearance of trying to save the empire while secretly planning its demise. As the story is told from Airón’s POV, it was fun to read as Airón is super capable and a main character to root for, his love for Tallu drives all his actions, and he is admirable and intelligent as well. I thoroughly enjoyed this entry in the series, the group of supportive characters that are loyal, the commitment Airón and Tallu have to each other, and the overarching hope to bring about a better empire.
Profile Image for Copper.
351 reviews5 followers
March 24, 2026
Catching back up with Airón and Tallu as they continue their secret mission for the good of the empire and their own happiness. More court politics and political manoeuvring going on to keep you interested. But also a lot more history on the land and the people of the extended empire.

Seeing everything from Airón gives him a strong voice and I find his thinking can be hit or miss, giving interesting outcomes for both. This also gives Tallu some mystery over his interworking, although at this stage of the story they are both so manly in love that he's mostly thinking of the empire or Airón. I love how the pair have grown together and deeply love each other now.

Also love the pair of dogs Asahi and Sagam I wish we saw more so excited they are getting their own book soon. I find their love story so sweet but tragic, I really hope they can build some happiness.

Looking forward to the next book, the last few chapters here really had me going. I'm interested in how this next installment will play out after the event in this one.
Profile Image for Es :D.
24 reviews
April 4, 2026
This book was so good. 5 stars for me. The relationship of Tallu and Airón deepens, and we get to see more of their love for each other.

We also learn more about Sagram, who was a bit more a minor/side character in the first few books. We learn more about his family and origin.

I also love the fact that we get to see more of Airón’s power in this story. He’s really powerful, and we get a contrast later in the story. ( spoilers) About him and Seagram’s sister, Riini. Riini sacrificed almost everything in her life to try and regrow an elder tree. While Airón easily grew many with his memories.

It saddens me that Tallu has to accept his bloodline, and become someone he desperately tried not to become. I guess the title of the fifth and final book, Crown of Ash, suggests what might happen at the end of this series.

“I am going to save you, Tallu.” I gripped his face between my hands. “Do you hear me?”
“You regrew an elder tree for me?” He let my braid slip from his fingers, lifting another.
“I learned forest magic for you,” I said.
This entire review has been hidden because of spoilers.
Profile Image for Avid Reader 1.
838 reviews1 follower
March 18, 2026
4 ¼ Stars

Dragon Blood Curse is a great continuation of the Emperor's Assassin series. I strongly recommend rereading previous books in this series before reading this one.
Tallu and Airón continue to support each other and their goals for the empire's future. There is A LOT of political talk in the first half of the book. It lost my focus at times, but I’m not a big political person, so I guess that’s a “me” thing. Many of the characters will receive the side-eye since I have become suspicious of almost everyone on these pages. The depth of the characters and the worldbuilding in general continue to impress me.
Airón and Tallu are wonderful main characters, and I feel closer to them with each successive book. Even with the single POV, I know Tallu just as well as I know Airón.
I am invested in the lives and HEA of these two and in the outcome of their political partnership.
I look forward to more from this author.
Profile Image for Andi.
140 reviews
May 22, 2026
The beginning was really slow and it felt like it took a long time before it finally starts picking up. It took me much longer to get into this book than previous books. I thought this was the last book of the series I wasn't aware we were going to number five. So I was worried when I was 70% of the way in and things you thought were about to happen....weren't even close to happening. (Cool way to learn there is another book tho!!) I do wish the last half of the book was the longer and the first half was much shorter, if that make sense. The last half of the book had all the cool interesting plot points and it felt like we were just speeding through them while we were dragging our feet with political alliances.

Married husbands would die for each other I love that I get you for one more book.
Profile Image for She Who Shall Remain Nameless .
299 reviews
Review of advance copy received from Author
February 27, 2026
Excellent new addition to the series! I highly recommend rereading the previous book in this series before reading the new releases just to reacquaint yourself with the storyline. I purchased this book directly from the author, which I highly recommend as a way to both support your favorite authors and not spend money with Amazon. This book helps further Airon and Tallu’s quest. There was a bit more political intrigue in the first half of the book than I prefer, but the second half had a bit more action to it. Overall, this is an excellent series which I highly recommend. I can’t wait for book 5 to be released.
Profile Image for Juniper.
3,506 reviews24 followers
March 16, 2026
This is book 4 in the series, and a gentle note to readers that starting at the beginning is a good idea. This book delivers everything that’s made this series so compelling: immersive, layered world building that blends magic, intrigue, wonder, and genuine peril in a way that never loses its sense of stakes, and absolutely no dull moments (plenty happens, and I’ll leave it at that — the plot deserves to be experienced on its own terms). What anchors it all, though, is Tallu and Airon, whose connection is a real source of strength and depth — for each other and for the story.

*I voluntarily reviewed a complimentary copy of this book
Profile Image for Deanna.
327 reviews1 follower
April 13, 2026
This series is so good. Like the others, this book catches you and drags you in from start to end. There's more politics (which Airon might think he's bad at but I think he's catching on) more magic, more blood. More sacrifce. The journey to save Tallu and Hallu continues, and the prophecy which started this whole mess becomes clearer. Kai Butler's writing is so rich - the journey through the empire and Tavournai itself was so brilliantly described it felt like I was there. I worry for Asahi and Sagam, and Iradio. Looking forward to the next book.
Profile Image for Hallowchaser.
14 reviews
July 3, 2026
book four didn't disappoint. we got more political intrigue again, which is the main reason i enjoyed book one as much as i did.

we finally did get to know some side characters a bit better. i still wish they would get more screen time though. it makes sense within the story that we don't know much about them though.

the story took a great turn and i really liked the setting of this one, especially compared to book three.

is our mmc a bit overpowered? possibly. we keep seeing him struggle though.

the wait for book five starts now.
Profile Image for Natasha.
195 reviews
July 16, 2026
Struggling to enjoy this book with even a fraction of the other books. Cannot keep up with who did what and why someone was beheaded.

Too much “I’m the emperor how dare you question me”

What are we trying to do here? 1/2 way through and I still can’t decide where they’re going. To kill the other general or to Spider?

“And she had no twin to share the weight of it”. Having a twin does not mean 1/2 the problems because you can share, it means twice as much because TWINS ARE TWO DIFFERENT PEOPLE.

Probably would have been a 3 star but I could deal with the twin crap anymore.
Displaying 1 - 30 of 58 reviews