The Gilded Ones by Aminatta Forna

In a world where purity is determined by the color of one's blood, a young girl named Deka faces a life-altering test that reveals her true nature, setting her apart from her peers. Marked as an outcast, she is given a choice: face a grim fate or join an elite group of warriors known as the Alaki, who possess extraordinary abilities and are tasked with defending their kingdom from monstrous threats. As she embarks on this perilous journey, Deka uncovers hidden truths about her past and the oppressive society she inhabits, challenging her to redefine her identity and embrace her newfound power.