The Empyrean series saw a major new release with Onyx Storm earlier this year, propelling all three books to the top of Amazon's Kindle bestsellers list for 2025. The series' popularity surged with the initial publication of Fourth Wing in 2023, largely fueled by the BookTok community. Since then, this romantic fantasy series has grown into a phenomenon, dominating numerous bestseller charts.

The influx of new readers following the launch of Onyx Storm underscores the viral appeal of Rebecca Yarros' writing. It strikes the perfect balance of fantasy and romance, captivating a wide audience. With a Fourth Wing TV series officially greenlit by Amazon, The Empyrean series has the potential to rival, or even surpass, the popularity of franchises like Harry Potter if its momentum continues.

The Physical Editions Are Popular Too

Onyx Storm (Deluxe Limited Edition)

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While The Empyrean series rules the Kindle charts, it also features prominently on Amazon's list of top-selling print books for 2025. Both the deluxe and standard editions of Onyx Storm are in the top 10, with Fourth Wing also holding strong in the top 25.

Onyx Storm has only been recently displaced as the top fiction title by the official release of Suzanne Collins' new Hunger Games novel. However, with a steady stream of new readers discovering the series through Fourth Wing, its ranking could easily shift again before the year ends.

Fourth Wing and Iron Flame are Part of Kindle Unlimited

Kindle Unlimited

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The first two books in The Empyrean series are currently included for free on the Kindle app with an active Kindle Unlimited subscription. If you're looking to start the series, you can log into your Kindle account to download both Fourth Wing and Iron Flame while they remain available through the program.