The Empyrean series has soared to new heights with the release of "Onyx Storm" earlier this year, propelling all three books to the top of Amazon's Kindle best sellers list for 2025. The series' meteoric rise began with the publication of "Fourth Wing" in 2023, largely fueled by the viral sensation of Booktok. Since then, Rebecca Yarros' romantasy series has captivated readers worldwide, dominating bestseller charts with its perfect blend of fantasy and romance.

The viral success of "Onyx Storm" has not only drawn new readers to the series but also highlights the magnetic appeal of Yarros' storytelling. With the announcement of a "Fourth Wing" TV series now greenlit at Amazon, the Empyrean series is poised to potentially eclipse even the Harry Potter franchise in popularity, provided it capitalizes on this momentum effectively.

The Physical Editions Are Popular Too

Onyx Storm (Deluxe Limited Edition)

1. See it at Amazon
2. See it at Barnes and Noble
3. See it at Target

While the Empyrean series reigns supreme on Kindle charts, it also holds a strong presence on Amazon's list of top-selling physical books for 2025. Both the deluxe and standard editions of "Onyx Storm" rank within the top 10, with "Fourth Wing" maintaining its spot in the top 25. The recent release of Suzanne Collins' new Hunger Games book has nudged "Onyx Storm" to the second spot on the fiction list, but with more readers discovering the series through "Fourth Wing," the rankings could shift again before the year ends.

Fourth Wing and Iron Flame are Part of Kindle Unlimited

Kindle Unlimited

35. See subscription options.
36. See it at Amazon

For those eager to dive into the Empyrean series, "Fourth Wing" and "Iron Flame" are currently available for free on the Kindle app with a Kindle Unlimited subscription. Subscribers can easily access these titles by logging into their Kindle account and downloading the books before they potentially exit the subscription service.