Afterfire

Camren, known as Six and called Cinder by others, discovers he can command lightning and wind in a post-apocalyptic world where Black elemental people were enslaved by royal powers and later believed extinct. When authoritarian royals invade his city, kill those who resist, and enslave survivors, Six fights back and kills several soldiers before a powerful royal defeats him. Stripped of his real name and freedom, Six must uncover the truth and decide what freedom and power mean in a world still shaped by that history.