Power, Rory. Wind-Up Garden series #2

"The Argyros siblings have lost everything. With their father dead and their family home captured, they're no longer the rulers of their fractured kingdom--and no longer bound to each other. In the frozen north, Rhea struggles to wield her newly inherited command over death and to find her place in an increasingly distrustful rebel group. Chrysanthi travels to a distant, war-torn land in search of her elusive brother Nitsos, certain that he is there on a dangerous mission to restore the family to its former glory, this time with himself at its head. And Lexos, now stripped of all his power and a political prisoner of the Domina family, is left to rot in a hauntingly desolate palace with nothing but thoughts of revenge. Alone and farther apart than they've ever been, the siblings must reckon with the pain of their past and find a new path forward--or risk their own destruction"--