PHILADELPHIA — Author Rebecca Yarros posted an Instagram Reel on March 19, 2026, announcing she was officially writing the fourth novel in her Empyrean series. In the video, she walked up to a board and wrote "#4" at the top.

The announcement marked her return to the fantasy series after completing a contemporary novel. In the Instagram caption accompanying the March 19 Reel, she wrote that once her latest contemporary novel was off to her editor, she was back writing in the Empyrean world.

The fourth book will continue the story that began with Fourth Wing in April 2023 and continued through Iron Flame in October 2023 and Onyx Storm in January 2025. The Empyrean series is set to comprise five novels, all published by Entangled's fantasy imprint Red Tower.

On January 25, 2025, she said at an engagement in Philadelphia that she would not commit to a release date for the fourth Empyrean novel because she was writing a contemporary novel first. She told Elle she intended to rest before returning to writing because her workload in recent years had adversely affected her mental and physical health.

The author began preparing for the fourth novel in early 2026. On January 24, 2026, she posted on Instagram that the fourth Empyrean novel would be next in her writing schedule after she finished the contemporary novel she was writing. "Book 4's playlist is simmering and I'm almost ready for the index cards and plot board," she wrote.

On February 8, 2026, she posted a photo of her desk showing the Empyrean novels, a stack of index cards, and two Sharpies. She captioned her February 8, 2026 Instagram post with the hashtags #plotting, #book4, #Empyrean, and #fourthwing, indicating she had started plotting the fourth Empyrean novel.

Onyx Storm was the fastest-selling adult novel released in the past 20 years and ended on a cliffhanger. At the end of Onyx Storm, Xaden used more of his venin power and embraced the dark side of his transition, while Violet Sorrengail woke up with a wedding ring, a blessing of her marriage to Xaden from the goddess Dunne, and no memory of the previous 12 hours.

In June 2025, she shared on Instagram that she had started writing a new contemporary novel. She said she planned to take time off to be with her family before writing the fourth Empyrean novel.

She has Ehlers-Danlos syndrome and postural orthostatic tachycardia syndrome (POTS). She makes playlists to reflect the mood and plots of her novels and uses notecards to create a cohesive timeline when plotting her novels.