Cruel Fates · 2025
Once Upon a Demon's HeartSpice level, tropes & is it dark romance?
Spice 4/5 (Explicit) · Darkness 5/5 (No light) · 11 trigger warnings flagged
From K.M. Moronova, 2025: Once Upon a Demon's Heart, book 1 of Cruel Fates. The pull here is enemies to lovers, fae, demon, gothic, war and morally grey. We score it spice 4 (explicit) and darkness 5 (pitch black). The heaviest flags readers report are blood, violence, war. Our scores lean on what readers report, not on a full reread, so treat them as a guide. This note is ours. It is not a publisher blurb.
First published: 2025. Book 1 of Cruel Fates.
Once Upon a Demon's Heart tropes
On this shelf, Once Upon a Demon's Heart is filed under Enemies to lovers, Fae romance, Demon romance, Gothic romance, War romance and Morally grey heroes. Each tag opens more books with that trope.
Once Upon a Demon's Heart spice level
Is Once Upon a Demon's Heart dark romance?
Yes, at the very dark end. Once Upon a Demon's Heart scores 5 of 5 on our darkness scale (No light).
Spice and darkness are separate scores. More no light books. How we rate.
Once Upon a Demon's Heart trigger warnings
Book-specific flags taken from reader-submitted content warnings on The StoryGraph (top flag reported by 31 readers), grouped by us. Also on that list: sexual content, death of parent, toxic relationship, injury/injury detail, child death. See the reader-submitted list.
Graphic (11) — open before you read
Open this before you read. These are the flags most likely to be a hard stop.
Moderate (0)
Harm, control, or obsession that is common in this lane.
None flagged in this band.
Minor (0)
Present, and usually not the reason someone puts the book down.
None flagged in this band.
Full Once Upon a Demon's Heart trigger warnings
Cruel Fates reading order
Once Upon a Demon's Heart is book 1 of 1 in K.M. Moronova's Cruel Fates series. Start here.
- Book 1 Once Upon a Demon's Heart (this book) · 2025
Order checked against the StoryGraph Cruel Fates series page on 13 October 2026.
Who it's for
Shelf note written for this site. We do not copy reviews or publisher blurbs. Outbound links are search pages, not quoted ratings. Kindle Unlimited and endings are only flagged when we were willing to mark them. How we rate.
Missing a book? Suggest it.
Books like Once Upon a Demon's Heart
Matched on shared tropes, then the closest spice and darkness scores. Other books in the same series are listed above, not here.
- Their Vicious Darling
Their Vicious Darling
Nikki St. Crowe
Spice ●●●●○Dark ●●●●●
Shared: Enemies to lovers, War romance
- Fairydale
Fairydale
Veronica Lancet
Spice ●●●●○Dark ●●●●●
Shared: Fae romance, Gothic romance
- The Unseelie Throne
The Unseelie Throne
Kathryn Ann Kingsley
Spice ●●●●○Dark ●●●●●
Shared: Enemies to lovers, War romance
- Dawn of Chaos and Fury
Dawn of Chaos and Fury
Melissa K. Roehrich
Spice ●●●●○Dark ●●●●●
Shared: Morally grey heroes, Fae romance
- Deviant Hearts
Deviant Hearts
Jagger Cole
Spice ●●●●○Dark ●●●●●
Shared: Enemies to lovers, War romance
- Devil
Devil
Ker Dukey
Spice ●●●●○Dark ●●●●●
Shared: Gothic romance, Morally grey heroes
- How Does It Feel?
How Does It Feel?
Jeneane O'Riley
Spice ●●●●○Dark ●●●●●
Shared: Fae romance, Morally grey heroes
- Demon with Benefits
Demon with Benefits
Aurora Ascher
Spice ●●●●○Dark ●●●●●
Shared: Enemies to lovers, Demon romance
Books like Once Upon a Demon's Heart, with a reason for each
Questions readers actually ask
What is the spice level of Once Upon a Demon's Heart?
Once Upon a Demon's Heart spice level is 4 of 5 (Explicit). On-page sex, clearly written. Darkness is a separate score: 5 of 5 (No light).
What are the Once Upon a Demon's Heart trigger warnings?
Graphic: Blood, Violence, War, Death, Grief, Murder, Sexual assault, Psychological abuse, Abuse, Gore, Torture. Moderate: none flagged. Minor: none flagged. These are book-specific flags reported by readers on reader-submitted content warnings on The StoryGraph (top flag reported by 31 readers), grouped by us. The author's own note may list more. Read it before you start.
Is Once Upon a Demon's Heart dark romance?
Yes, at the very dark end. Once Upon a Demon's Heart scores 5 of 5 on our darkness scale (No light). The book is not interested in pulling the punch.
What tropes are in Once Upon a Demon's Heart?
On this shelf Once Upon a Demon's Heart is filed under Enemies to lovers, Fae romance, Demon romance, Gothic romance, War romance and Morally grey heroes.
Who is Once Upon a Demon's Heart for?
Pick this up if you want enemies to lovers and fae with explicit spice. Look at the warnings before you commit.
What are some books like Once Upon a Demon's Heart?
Matched on shared tropes and similar spice and darkness: Their Vicious Darling by Nikki St. Crowe; Fairydale by Veronica Lancet; The Unseelie Throne by Kathryn Ann Kingsley; Dawn of Chaos and Fury by Melissa K. Roehrich; Deviant Hearts by Jagger Cole; Devil by Ker Dukey. More read-alikes, each with a reason, are on zademasked.com/like/once-upon-a-demon-s-heart.
Is Once Upon a Demon's Heart a standalone?
No. Once Upon a Demon's Heart is book 1 of 1 in the Cruel Fates series by K.M. Moronova.
What order should I read the Cruel Fates series in?
1. Once Upon a Demon's Heart.
How many books are in the Cruel Fates series?
The Cruel Fates series by K.M. Moronova has 1 main book.
What is the Once Upon a Demon's Heart age rating?
We'd say 18+. Spice sits at 4/5 (explicit) and darkness at 5/5 (no light). That's our recommendation, not an official rating, so read the trigger warnings as well.
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