4.3 (6,333 ratings)

Once upon a Demon's Heart: Cruel Fates Duet, Book 1

Name: Once upon a Demon's Heart: Cruel Fates Duet, Book 1
Rating: 4.3 (6333 reviews)
Author: K. M. Moronova
ISBN: B0FLF8G27J

by K. M. Moronova

demons

About this book

This is no fairytale; it's the yearning and guilt of two burdened hearts that will leave you breathless.

Alira, a devoted demigod knight, has found herself trapped in the throes of a brutal curse—a time loop in which the demon kingdom's Blood Knight kills her every time. She is haunted by the attack she led on the innocent village of Thornhall, and her guilt consumes her from the inside out. After the twentieth time loop, she has finally had enough. Something has to change, lest she die at the Blood Knight's hand for the rest of time. A choice she hopes she won't regret—one to end the war between demigods and demons. Alira is shocked when she realizes that she's marrying the very knight who has slain her so many times.

A daughter of Venus and a duke of demons. Their love is both cursed and destined—a marriage to save the fragility of their kingdoms.

Kalel is as cruel as they come. A devourer who survives on the gilded blood of demigods. He wants to hate her as much as he did when Thornhall fell, but he finds himself warring with his heart over his emotions for her. Together, they unravel the truths of Faultore, that perhaps not everything is as it seems. The gods may be pulling more strings than they should.

It's not a question of what love can conquer; it is a matter of what they are prepared to demolish in the path of it.

Narrated in duet style.

Publication Date: May 25, 2026
ASIN: B0FLF8G27J

Reader Reviews

He Killed Her 99 Times. She Married Him Anyway.

November 30, 2025

This romantasy swept me away with its emotional depth, mythic stakes, and unforgettable characters. It’s a fast-paced, enemies-to-lovers tale that blends divine curses, political tension, and slow-burn romance into something truly unique. Alira, a demigod knight, is caught in a brutal time loop—dying again and again at the hands of Kalel, the demon Blood Knight. Her only escape? An arranged marriage to the very enemy who’s been her executioner. What follows is a tense, emotionally charged...

A slow burn that pays off

March 24, 2026

I loved this book/author so much that I have started replacing her books with hardcover editions. This story is unique and keeps your attention from cover to cover. Maybe I am a sucker for K.M. Moronova, but I am 100% okay taking that to the grave. Her stories captivate me every single time, and I am hooked. With this story, the FMC is killed in a time loop for 20 years! I love it when you start to feel the characters really struggle with their feelings. This is more of a slow burn than many of...

I need the second book

November 14, 2025

“You should know that I die slowly with each tear you shed. I love you, Alira. I'm sorry for what I am.” 😭😭😭 K.M. Moronova writes like her pen is dipped in sin and sorrow, and this book is nothing short of a haunting poem I'll never forget. Her writing is equal parts poetic and seductive, aching with longing, laced with violence, and so rich in emotional texture that I swear I could feel the heartbreak soaking into every page. Alira and Kalel are two broken souls shackled by fate, reliving a...

Unique and Quick Read

August 5, 2025

I wanted to read this book after reading a lot of good reviews and seeing it advertised online. I was not disappointed, the plot is good, it’s true enemies to lovers. My only complaint is that the female character lacks resolve. She is made out to be a soldier from her kingdom yet she is constantly portrayed as a damsel in distress. The only time she actually fights something and they’re not even hurt, just transformed into flowers… not my favorite thing ever. She is overall a pretty weak...

A strong enemies-to-lovers romantasy with intense chemistry and emotional depth.

April 14, 2026

⭐ Once Upon a Demon Heart ⭐ 5 Stars | 🌶️🌶️🌶️🌶️ A strong enemies-to-lovers romantasy with intense chemistry and emotional depth. While the story is built around vengeance, regret, and conflict, the romance between the main characters never gets overshadowed. Their connection feels raw and real, with both characters showing enough awareness and growth to make their dynamic believable and engaging. The romance is a fast burn physically but slower emotionally, which creates a great balance...