Blood Soldiers: The Second Army - Grishaverse Prequel

WARNING: SPOILERS FOR SHADOW AND BONE SERIES

Before he became the Darkling, Aleksander was just a boy hoping to build a world where all Grisha could be safe.
When he and his mother travel to a small Grisha safe-haven, he meets a Yelena, a Grisha Heartrender with the same dream.
Together, they set out to change the world by building the Second Army, a place where Grisha learn to use their powers and become the most fearsome soldiers the world has ever seen.