If you've finished Onyx Storm and need something to fill the gap before Book 4, these books share specific DNA with the Empyrean.
Spark of the Everflame by Penn Cole has the same indie-to-massive trajectory that Fourth Wing had. A mortal woman forced into an immortal world, slow-burn romance with genuine antagonism, and political stakes that escalate across the series. The Kindred's Curse Saga is heading to Hulu, so you can get in before the adaptation.
The Serpent and the Wings of Night is the closest match for readers who want the deadly competition dynamic. Oraya is a human raised among vampires, entering a tournament where she's the most vulnerable participant. The romance with Raihn builds through forced alliance and mutual survival. If Violet's underdog energy hooked you, Oraya's will do the same.
When the Moon Hatched by Sarah A. Parker is for readers who want more dragons. The Moonfall series puts dragon-bonded characters at the center of a story about grief, rage, and a love that spans lifetimes. The sequel, The Ballad of Falling Dragons, drops May 19, 2026.
An Ember in the Ashes by Sabaa Tahir takes the military academy setting and makes it darker. Laia infiltrates a brutal training institution as a spy. The romance is forbidden and builds across four books. If you loved Basgiath's danger but wanted more political resistance, this series delivers.
Throne of Glass by Sarah J. Maas is the obvious comp for readers who haven't gone there yet. An assassin in a deadly competition, a slow-burn romance that evolves across the series, and a world that expands dramatically from where it starts. Maas wrote the template that Yarros built on.