The Empyrean series has taken the literary world by storm, with the latest installment, *Onyx Storm*, released earlier this year, propelling all three books to the top of Amazon's Kindle best sellers list for 2025. The series' surge in popularity began with the release of *Fourth Wing* in 2023, fueled by the viral power of Booktok. Since then, Rebecca Yarros' romantasy series has captivated a diverse audience, blending fantasy and romance in a way that has kept readers hooked.
Amazon best selling kindle books
The release of *Onyx Storm* has not only attracted new readers but also showcased the infectious enthusiasm surrounding Yarros' work. With a *Fourth Wing* TV series now greenlit at Amazon, the Empyrean series has the potential to outshine even the iconic Harry Potter franchise, provided it continues to engage its audience effectively.
The Physical Editions Are Popular Too
### Onyx Storm (Deluxe Limited Edition)
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Beyond the digital realm, the Empyrean series has also claimed a significant presence on Amazon's top-selling physical books list for 2025. Both the deluxe and standard editions of *Onyx Storm* rank within the top 10, while *Fourth Wing* secures a spot in the top 25. The only book to momentarily eclipse *Onyx Storm* is Suzanne Collins' new addition to the Hunger Games series. However, with an influx of new readers discovering the series through *Fourth Wing*, *Onyx Storm* could reclaim its position before the year's end.
AnswerSee ResultsFourth Wing and Iron Flame are Part of Kindle Unlimited
### Kindle Unlimited
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For those eager to dive into the series, *Fourth Wing* and *Iron Flame* are currently available for free on the Kindle app through a Kindle Unlimited subscription. Subscribers can easily access these titles by logging into their Kindle account, ensuring they don't miss out on this captivating series before the books potentially leave the subscription service.
