The Castle Cycle is a series of New Weird novels by Steph Swainston, comprising a total of five novels, with four, The Year of Our War, No Present Like Time, The Modern World, and the most recent, Fair Rebel, following a main narrative and another, Above the Snowline, acting as a prequel to the series.
The Fourlands is an ancient, sprawling empire, spanning the entirety of the known world and suffering slow decay by way of an eternal war with the enormous, ant-like Insects in the north. In the center of the empire, from the Castle, reigns the Emperor San, an immortal who has ruled over the empire since its formation centuries ago. Supposedly granted immortality and the power to bestow it on others by God when it mysteriously left the world in times past, San holds a council of fifty Immortals, or Eszai, at his beck and call, each chosen for their unrivalled skill and knowledge in a particular facet of war. These immortals are the highest officials and warriors of the Fourlands, sent forth to the front when needed and otherwise serving as strategists and tactical advisors.
Enter Jant Shira, known as Comet, Messenger of the Immortals and the only man in the world that can fly. Moving in and out of addiction due to the stresses of the job, the series chronicles various intervals of relapse and progress in the war against the Insects. What ensues from Jant's actions, and those of his fellow Immortals, is a story of loss, tragedy, betrayal, sex, and greed that shows the darkest side of men and women that are meant to be paragons of virtue and wisdom, but are often anything but.
The series is still ongoing. The first book, The Year of Our War, was released in 2004; the second, No Present Like Time, in 2006; the third, The Modern World, in 2007; the most recent addition to the series, Fair Rebel, was finally released, after a long hiatus, in 2016. A prequel tie-in novel, chronicling a segment of Jant's life before his rise to immortality, titled Above the Snowline, was released in 2010.