Record of Zako War
In this universe, the Master clans raise into the power while stepping on the bloodshed of lower-class Noumas. Shad Walharwdo, the son from a noble family, and his childhood friend, Pell Dehawson were expected to sacrifice many Nouma souls for their coming-of-age ceremony. But Shad wasn't ready to dirty his hands, despite the expectation as the future clan successor. What would happen to him when the social system collapse and the superior power is being toppled down by the might magic? To not kill is probably not a choice anymore.