Beasts Made of Night by Tochi Onyebuchi
In the walled city of Kos, corrupt mages can magically call forth sin from a sinner in the form of sin-beasts '? lethal creatures spawned from feelings of guilt. Taj is the most talented of the aki, young sin-eaters indentured by the mages to slay the sin-beasts. But Taj's livelihood comes at a terrible cost. When he kills a sin-beast, a tattoo of the beast appears on his skin while the guilt of committing the sin appears on his mind. Most aki are driven mad by the process, but 17-year-old Taj is cocky and desperate to provide for his family. When Taj is called to eat a sin of a royal, he's suddenly thrust into the center of a dark conspiracy to destroy Kos. Now Taj must fight to save the princess that he loves '? and his own life. A gritty Nigerian-influenced fantasy.