Threshing Day, the latest entry in the Empyrean series released Sept. 29, is a novella in the Fourth Wing universe. It features 13 short stories, each one focused on a character from the mainline books. The first chapter focuses on Brennan Sorrengail, Violet and Mira’s older brother. It gives us some insight into the family as a whole and Brennan’s love life. But most striking of all is that it confirms something about Brennan that fans have theorized for quite some time.