Fourth Wing Books Top Amazon's Kindle Best Sellers in 2025

The Empyrean series made a major splash in early 2025 with the release of *Onyx Storm*, and now all three books are dominating Amazon’s Kindle best sellers list for the year. The series first gained momentum when *Fourth Wing* launched in 2023, largely thanks to the influence of BookTok. Since then, this romantasy sensation has grown into a powerhouse, consistently ranking at the top of most major best seller charts.

The success of *Onyx Storm* highlights the viral appeal of Rebecca Yarros’ storytelling. With its perfect blend of fantasy and romance, it's no wonder readers across genres have fallen in love with the series. Now that Amazon has greenlit a TV adaptation of *Fourth Wing*, the Empyrean universe has the potential to surpass even the legendary popularity of the *Harry Potter* book franchise—provided it continues on this upward trajectory.

The Physical Editions Are Popular Too

Onyx Storm (Deluxe Limited Edition)

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While the Empyrean series is dominating the Kindle charts, it's also making waves in physical book sales. Both the deluxe and standard editions of *Onyx Storm* are currently ranked within Amazon’s top 10 physical books for 2025, and *Fourth Wing* remains in the top 25.

Only with the recent release of Suzanne Collins’ new *Hunger Games* installment has *Onyx Storm* slipped to the second most popular fiction book. However, considering how many new readers are just now discovering the series through *Fourth Wing*, it wouldn’t be surprising to see it climb back up before the end of the year.

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Fourth Wing and Iron Flame Are Part of Kindle Unlimited

Kindle Unlimited

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If you're looking to start the Empyrean series without spending extra, both *Fourth Wing* and *Iron Flame* are available for free via Kindle Unlimited. Take advantage of your subscription and download both titles before they potentially rotate out of the program. It’s a great way to experience the beginning of this blockbuster series risk-free.