Their Will Undone

by R.J. Valldeperas

A debut YA fantasy must-read for fans of The Winner’s Curse, What the River Knows, and This Woven Kingdom.

When a maiden is selected to marry the emperor, her journey to the palace will see her fighting both a spark of magical power and her growing feelings for her broody escort in this romantic fantasy duology opener, inspired by a true story from the Inca empire. 

In Amaru, it is an honor to be chosen in the annual harvest and serve the gods'-favored emperor. Nina’s brother has already been chosen, but when the emperor’s men come a second time for her sister, Nina volunteers instead. She is taken to the acllahuasi, a gilded cage where women train to become servants or wives for the ruling class. It is there that a soldier comes to collect her, and Nina learns of her fate—to become a wife...to the emperor.

As the emperor's trusted friend and soldier, Kasik is ordered to retrieve Nina and deliver her untouched. But the emperor’s betrothed is not as he expected. The distrust between Nina and Kasik is thicker than the trees surrounding them, and Kasik’s honor is put to the test when their path back to the capitol leads them into dangerous territory. Their lives and hearts are in peril as forbidden desires are unearthed, along with a stirring of dark magic in Nina that inexplicably ties her to the gods.
What begins as a simple task becomes a tense journey that forces Nina and Kasik to confront where their true loyalties lie—with the emperor and the fate of their people, or with the desires of their own hearts.

Genres: Fantasy, Young Adult, Fiction, Young Adult Fantasy, Science Fiction Fantasy, Historical Fiction, Historical

Unknown Binding

Expected publication June 2, 2026

About the author

RJ is a Peruvian/Venezuelan writer from Florida, where she lives with her husband, five children, three goats and nine chickens. When she’s not playing chauffeur or chef, she spends her time creating stories steeped in culture with characters who look just like her, or she’s shirking all responsibility to escape into the pages of someone else’s world.

Reviews

[jenny reads a lot · Rating 4 out of 5]

Their Will Undone has a rich, interesting world and magic, feminine rage, and kicking you feet and giggling romance!

I think this is a well executed YA fantasy and will wok very well for YA readers!

Whats to love…
- interesting, richly detailed world
- political machinations
- simmering feminine rage
- well executed micro tropes that’ll have you squealing!
- touch her and ☠️
- chosen one (a personal fav)
- only one (animal mode of transport)
- hand flex

What didn’t work for me…
- I think the author does a decent job showing you the world & the magic, but when it comes to emotions the book relies heavily on telling you how the characters are feeling rather than showing you how they feel. This became a bit repetitive, because even in cases where we were shown the emotions, it was followed up the exact details, telling us how we were to interpret those signals. I prefer a little less explanation and a little more faith in the reader to understand what we’re being shown. Granted this is a YA book, so a bit of hand holding is to be expected but it felt overly so at times.

| IG | TikTok |

Thank you to the publisher for the gifted book. All opinions are my own.

[Lindsey Robison (theinfernalqueen)]

JUST ME PATIENTLY (not patiently) WAITING

[Starr ❇✌❇]

"the first book in a debut YA fantasy duology in which an Inca girl imprisoned in a priestess temple is summoned to the palace by an unexpected marriage proposal from the emperor, and must contend with both his infuriatingly handsome right-hand man and the dark magic growing inside her—and decide whether she'll be a bride or a weapon."

[Breanne Randall · Rating 5 out of 5]

Literally just waiting with bated breath. Everyone add this to your tbr!!!!

[Chloe · Rating 5 out of 5]

Oh, this was absolutely incredible. It's everything that a YA fantasy should be, and the perfect mix of both anger and love. There is such a rich world, with such rich characters. It's utterly spectacular.

[Priscilla · Rating 5 out of 5]

✨Stay calm and in control. Do not let them see what you love. It is the only power that matters, and you are its only master✨

✨How strange it was to have the power to choose, and what a privilege✨

✨If I am a monster for protecting them. Then so be it. ✨

✨They couldn’t be friends, but he didn’t want to be her enemy ✨

✨No longer was she a forgotten nobody. No longer could she claim ignorance ✨

~

📖Summary:
Inspired by a true story from the Inca Empire, this debut YA fantasy duology opener will appeal to fans of The Winner’s Curse, What the River Knows, and This Woven Kingdom. When Nina volunteers to take her sister’s place as a chosen bride for Amaru’s god-favored emperor, she is taken from the acllahuasi and escorted to the capital by Kasik, the emperor’s loyal soldier. Their perilous journey through hostile lands ignites mistrust, forbidden attraction, and awakens a dark, divine magic within Nina that ties her to the gods themselves. As duty and desire collide, Nina and Kasik must choose between loyalty to the emperor and the fate of their people—or the pull of their own hearts.

🖊️💞My thoughts:

Now this—THIS—is a debut novel. Wow. Just… WOW. The world-building and cultural depth are nothing short of phenomenal, and R.J. masterfully pulls you into the story from the very first page. NOT A SINGLE MOMENT DRAGS—I was on the edge of my seat the entire time, completely consumed, like I was watching a high-stakes telenovela unfold. Every chapter raises the bar with nonstop action, suspense, mystery, and absolutely addictive political drama. The story is immersive without ever being confusing, flowing seamlessly and effortlessly. From the moment you open the book, you’re transported to another world—and there’s no chance to breathe. It’s exhilarating, unputdownable, and impossible to forget.
~
THE TWO MCs? I ABSOLUTELY LOVED THEM.
They are rich, layered, and unforgettable characters. Nina’s character development was handled beautifully- watching her grow into her strength felt earned and deeply satisfying. And Kamayuq—KASIK—oh my goodness!! THIS MAN. Seeing him come into his own was everything; I was rooting for him every. single. time. Dare I say it… Cyrus-level YEARNING. Yes, I said it. He became a new favorite almost instantly. My heart ached for him, for the impossible choices he had to make and the weight of loyalty he carried. He’s complicated, captivating, honorable—and devastatingly human (and let’s be real; it doesn’t hurt that he’s gorgeous). What makes them unforgettable is that both Nina and Kasik are loyal; both are desperately trying to do the right thing, and the reader is left rooting for both. You see every side, feel every conflict, and end up wrestling with their choices right alongside them. It’s emotional, powerful, and utterly consuming.
~
THE DIALOGUE AND TENSION BETWEEN THESE TWO?!
I could write a PhD dissertation on it and still not do it justice. OH. MY. GOSH. There was literally a moment where I had to shut the book, stare at the wall, and question my entire life because my brain couldn’t cope. INSANE. Their chemistry? Masterclass. Chef’s kiss. Hotter than the sun on a Texas summer day. I am not saying I fangirled uncontrollably… but my neighbors may have called the cops. Mark my words peeps: this is going to be one of the top debut fantasy novels of the year. Come June 2nd, if you don’t have this on your TBR, do you even like fantasy? I was genuinely heartbroken when it ended, like “where do I go from here?”. And Ms. R.J. Valldeperas, please accept my eternal loyalty & all pre-orders from now on — because I am counting the days until book two. Te amooo!
~
Huge thank you to NetGalley, HarperCollins Children's Books & R.J. Valldeperas for the ARC I am beyond grateful for the opportunity 💌.
All opinions are my own. Stay blessed, everyone!

[Kate · Rating 4 out of 5]

I really enjoyed the way the author weaved this story together with a cultural integration that really made it feel quite unique! The book itself is very well written, especially for a YA.

I do think the relationship part of the book could have used some work. It felt a bit stilted, and some of their behaviors were a bit infuriating to me. I also really, realllllly disliked the ending. It made it quite clear that this book is not a standalone, but I really don't like how it ends.

All that said, I did enjoy reading it and found it to be engaging and an interesting read.

Thank you to HarperCollins and Netgalley for the opportunity to read an advanced reader's copy. All opinions are my own and I was not required to leave a review.

[Lia Stevens · Rating 5 out of 5]

I haven’t read it yet. But — it’s gonna be good. This is just foreshadowing. 🫶🏽

[Wanderlust Booknook]

I see Inca I add to tbr

[Kristine Gift · Rating 2 out of 5]

*Disclaimer:* A digital ARC of this book was provided by NetGalley and the publisher in exchange for an honest review.

I had high hopes for Their Will Undone after following its author R.J. Valldeperas on Instagram for ages, but unfortunately I was disappointed. While the writing itself was fine (I’m likely to pick up new work from Valldeperas in the future!), there were three things that repeatedly took me out of the story that I just could not look past.

I am going to spoiler tag the bulk of my review, since I am reviewing so far ahead of release. I don't think that the points below are truly spoilers, but I want readers to be able to go in without any preconceived ideas if possible!

First, the timeline. The beginning of the book did not make any sense to me. It takes Kasik 15 days to get to the acllahausi where Nina is taken. However, she was on the road for 3 days, then is there for 10 days, locked in for 3 days before he arrives (16 days total). So somehow, Kasik was sent out 1 day after she was captured, but how did anyone know to send him? How would someone have communicated back to the emperor in a single day to tell him to send Kasik out? And then on the way back, Nina and Kasik are waylaid for 2 days, and yet make it back to Amaru Kancha in the same amount of time (or one day faster?) as it took Kasik on the way out. I know this kind of complaint sounds like a nitpick, but we were given explicit numbers on how long these journeys took, so the fact they didn't click was something I couldn't shake.

Second, Nina and Kasik have insta-lust which comes off kind of ick because she is 17 and he is… some age older than that. We never get his age, but I pinned him to be probably 20 or so. However I did not feel any chemistry between them, so the overtures in their internal narrations rang hollow. And the instant attraction between them impacts my third point.

Third, Nina and Kasik have wildly inconsistent internal motivations. Nina, when traveling the woods with Kasik, vacillates between feeling loyal to Kasik, to remembering she has to protect her sister, to thinking she wants to stay in the woods, to deciding to go the palace and do vengeance… but vengeance for what? We kept getting these reminders of how she is so full of rage, but it was never clear what she was enraged about. It felt hollow and forced on the reader and mentions of her rage rarely came up organically. And Kasik… somehow he is a disappointment to his father, who he hates, but wants to impress, and also he’s friends with the emperor, but doesn’t really like him, and maybe will abandon him for this girl he met two weeks ago. He just couldn’t pick a lane and I never had a good sense of who he was.

Between the timeline, the insta-lust, and the inconsistent motivations, I never settled into this book. I found myself frustrated with the characters more than rooting for them. Really bummed to be giving this such a low rating, but I think this needed some more time in the developmental stage before release to iron out some of the issues re: pacing and character work. That said, I think this will absolutely find its fans in the romantasy space, especially among fans of The Jasad Heir which has similar pacing/female rage.

[Laura Elisabeth · Rating 4 out of 5]

4 ⭐️

Thank you so much to NetGalley and the publisher for allowing me to read an ARC of this book. I am leaving this review voluntarily and all thoughts are my own.

Brilliant story with an intriguing world and a solid plot. I loved the writing and I think it had a really nice flow to it throughout the whole book. Great storytelling and wonderfully complex in its character arcs. I think Nina was such a strong main character to read about, and I especially loved the powerful ending and the way her rage is written and woven into the story.

I did have a few issues with Kasik and his blind loyalty... He had no trouble delivering (what he thought would be) a child bride to the emperor and had zero understanding for her situation and how it might not be seen as an honor for her when she is being forced to give herself and her body to a stranger who would be in complete control of her. I understand the purpose of showing us his unflinching loyalty and how he is shaped by the beliefs (and lies) of the people around him – I also acknowledge that he begins to question and challenge some of these beliefs later on and that it's a part of his growth and development. But: it's not the concept of the fact that girls and women are thought of as mere commodities to be traded around and used as "gifts" for powerful men that he begins to question – that's just the way it is, and it doesn't seem like he has any issue with this. But he does want to save this one particular girl, because he falls in love with her. Not because it's the right thing to do or because the whole foundation of their customs and their views of girls and women are horrible. At least that's what it seemed like to me, and I would have liked to see Kasik remove himself from this a bit more. I would like for him to feel bad, and not just because he wants to be with Nina.

I also struggled a bit with the fact that she is so young, and we know that he is older (we don't know exactly how much, but I'm assuming at least a few years). He is prepared for her to be a child (his words, not mine) and of course notices that she is older than what he initially thought – but he just found out (and still technically doesn't know how old she is yet), and yet he notices and stares at her naked thigh immediately and thinks about the way her body feels pressed against his. These are classic romantic tropes and I normally eat it up – it just felt a bit weird and inappropriate when she was so young and he was older and more powerful (in terms of position) than her. And I know it's a YA and therefore the characters are bound to be young, which is fine. It's just the fact that he wants her in a sexual way so early on and how that seems completely normal, and it just wasn't my favorite.

But overall, this was a strong book with a great premise and an insane ending (that I loved!), and I am very excited to see where everything goes from here.

[Julia Rachelle · Rating 5 out of 5]

⚔️Their Will Undone⚔️

Prepare to hear me shout about this book from the rooftops because it was SO GOOD!! I’ve been excited to read TWU since before it was picked up by a publisher, so when I was approved for an ARC on @netgalley, I was jumping off the walls in excitement😂

The author pitched this book as an “Inca inspired coming of rage fantasy” and it absolutely lived up to that description!

My favorite part of the book was the setting and culture. The author writes in such a way that I could hear the sounds of the forest and see the colors on the walls, and she brought a rich world inspired by the Incas to life so beautifully on the page.

Nina, our FMC, is kidnapped literally in chapter 1 and the rest of the book follows her journey to the emperor’s palace. Along the way, she discovers an abundance of secrets and lies that stoke her fury until eventually, she snaps. Kasik, on the other hand, is a loyal soldier and friend of the emperor who follows orders without questioning them, even when he’s sent to escort a mysterious girl back to the palace. They encounter their fair share of unexpected trouble along the way, and Kasik begins to realize that he too has been lied to and Nina is not all she seems. I absolutely loved his wrestle between being a good soldier and following orders or following in Nina’s footsteps to question those in authority. It’s rare for me to love an FMC and MMC the same amount, but I loved Nina and Kasik so much💛

The ending of this book was BRUTAL in the absolute best way and delivered everything I was hoping for and more. R. J. Valldeperas is an absolute genius, and I can’t wait to see how she finishes this story in Book 2! This book is especially close to my heart because I grew up in Brazil (admittedly not the region that used to be the Inca Empire), but I couldn’t be more excited to see more fantasy books inspired by South American culture and mythology hitting the shelves!

Their Will Undone releases June 2, 2026, so there’s still time to preorder!

[Mary Brahos · Rating 4 out of 5]

I first heard about Their Will Undone, a debut YA fantasy from RJ Valldeperas, on Instagram over a year ago and have been anxiously anticipating it since. Billed as an Inca-inspired "coming of rage" story, we follow Nina, a seemingly ordinary girl who volunteers as the emperor's chosen for the annual Harvest in an effort to save her sister, and later learns that she is destined to become his bride. Whisked from the chosen's acllahuasi by Kasik, the emperor's childhood friend and general, Nina must travel through a treacherous forest on her journey to the capital and uncover the meaning of a dark power that has recently awakened within her.

In Their Will Undone, Valldeperas has created an immersive and richly detailed world with memorable and multilayered characters. Nina in particular is everything I want in an FMC - smart, strong, and logical while remaining aware of her limitations and striving to adapt to whatever challenges come her way. The plot was well-paced and consistently engaging, and the climax truly made me gasp as all of the strings finally came together. While I wish elements of the magic system and the history of the gods were a bit more fleshed out, Their Will Undone is a strong YA debut and I am excited to see what Valldeperas has in store for us next.

Thank you to NetGalley and HarperCollins Children's Books for the ARC in exchange for an honest review!

[Nasrin · Rating 4 out of 5]

I rated this book 3.75 stars and rounded up to 4.
I was very intrigued with the book being inspired by a true story from the Inca Empire and the cover looking absolutely stunning.
Nina’s character development and her moral compass were done beautifully. She struggles with wanting to protect her family, especially her sister, and wanting to live her life on her terms. The same is with Kasik. He has known the emperor of most of his life and has been by his side essentially since childhood. He struggles with coming to terms with the fact that this was his friend and he is now doing some crazy things.
My biggest issue was the romance. It was trying its best to be enemies to lovers and at best it was annoyed to insta lust. The relationship wasn’t as developed as it needed to be for this book’s ending.

Thank you NetGalley for the eARC.

[sya ☆ · Rating 3 out of 5]

This one ended up being an okay read for me. The Inca Empire-inspired setting really caught my attention, and I liked Nina’s coming of rage arc. Unfortunately, I wasn’t a big fan of her love interest, Kasik, since I found him more frustrating than appealing, which made it hard for me to root for their relationship. The pacing also felt slow, especially in the first half, and it took a while for things to really pick up. I also wished the magic system had been explored in more depth. Still, I enjoyed this overall, and I think it was a good debut.

[Kie · Rating 4 out of 5]

Is it bad that I finished this in a day?

Thank you to Netgalley who gave me an ARC in exchange for a free review 💌

You dive straight into the story from the moment you turn to the first chapter, which I love!! The pacing of the story was perfect and I love how the author wasn’t afraid of giving her characters flaws. Also the YEARNING between Nina and Kasik is INSANE. The worldbuilding felt so unique and I loved every bit of it

[Shelby Schmidt · Rating 5 out of 5]

Thank you to NetGalley for this e-ARC.

A well-researched novel steeped in Andean history/mythology, stuffed with forbidden romance and political intrigue? Sign me up!

The gripping narrative is told by both Kasik's and Nina's point-of-view. Both characters have strong voices and are rich with personality. The plot is well-paced, keeping me engaged without stalling in the pages. I honestly couldn't put this story down and didn't want it to end!

[Megan Jauregui · Rating 5 out of 5]

I had the privilege of reading an early copy of Their Will Undone and y'all aren't ready. RJ Valldeperas flawlessly weaves together a complex and vivid world, characters you'd die for, a fresh magic system, and all the heartbreak and betrayal you can stand. I tore through this book and you will, too. Make way, Valldeperas is sure to be your next favorite author.

[Sydney Shields · Rating 5 out of 5]

So excited for this one!

[Meggo the Bookswan · Rating 5 out of 5]

This book can't come out soon enough! I'm patiently waiting and cheering you on!

[Desig · Rating 4 out of 5]

good book

[Isa · Rating 5 out of 5]

haven't read yet, but as a fellow peruvian, I'm dying to see what this book has in store.

[Gabic Reads]

Review coming at Gabic Reads. eARC received from Netgalley in exchange for an honest review.

[Kamilah Cole · Rating 5 out of 5]

Holy shit. I have no idea how this managed to be even better than I thought it would be from the description, but holy shit!!!

[Keziah]

Someone called this a coming-of-rage and I IMMEDIATELY added this to my tbr.