Get ready, riders: The long-gestating “ Fourth Wing ” TV adaptation has been ordered to series at Amazon ‘s Prime Video. Based on the best-selling “The Empyrean” romantasy book series from author Rebecca Yarros, “Fourth Wing” is set inside the brutal world of Basgiath War College, where there is only one rule: graduate or die. Twenty-year-old Violet Sorrengail was always expected to live a quiet life — but she’s sent on an entirely different path when her mother, a general in the military, orders her to join the hundreds of candidates striving to become dragon riders, the elite of Navarre. Yarros’ “The Empyrean” book series began with the release of New York Times best-seller “Fourth Wing” in May 2023, followed by sequel “Iron Flame” in November 2023 and third book “Onyx Storm” in January 2025. The titles and release dates for the planned fourth and fifth books have not yet been announced. Popular on Variety “Fourth Wing” executive producer Michael B.…