Ember in the ashes

"Laia is a Scholar living under the iron-fisted rule of the Martial Empire. When her brother is arrested for treason, Laia goes undercover as a slave at the empire's greatest military academy in exchange for assistance from rebel Scholars who claim that they will help to save her brother from execution"--

Beyond the Empire and within it, the threat of war looms ever larger as the Blood Shrike, Helene Aquilla, Laia of Serra, and Elias Veturius all face increasing dangers. The Blood Shrike, Helene Aquilla, is assailed on all sides. Emperor Marcus, haunted by his past, grows increasingly unstable, while the Commandant capitalizes on his madness to bolster her own power... the lives of all those in the Empire hang in the balance. Far to the east, Laia...

"Elias, Helene, and Tavi are Fivers - in training to become elite military recruits for the Martial Empire at Blackcliff Academy. When they're sent on a dangerous mission to steal a heavily-guarded poison on Isle South, the soon find themselves up against surprising enemies - including other recruits. As the true horror of their assignment is revealed, these three will begin to confront the harrowing realities of Martial rule, their place in the system...