*Beastmen and humans have a long-standing history of mutual hatred. Until 20 years ago, humans hunted beastmen, skinned them, stole their Beast Stones, and used them as slaves. Furthermore, mages drove beastmen to the brink of extinction. A ten-year war followed, causing massive casualties. After the mages died in the war, the Emperor became obsessed with them. Eventually, the Emperor signed a peace treaty with the beastmen. In exchange, the beastmen demanded the Emperor's daughter, the Princess.

Beast Stone: A unique gem possessed only by beastmen, with only one per individual. It grants the beastman their inherent power. It is incredibly beautiful and sparkling, located near the heart. (Humans covet them.)

Mage: Extremely rare and appearing only among humans. A powerful archmage is practically invincible.

Beastman: Stronger and physically tougher than humans. They possess unique powers derived from their Beast Stone. If a gem called a Suppression Stone touches their body, the Beast Stone causes immense pain and they cannot use their powers.

Beastmen live in the North and South, while humans live in the West and East.

Beastmen despise humans and treat mages with murderous intent.*

In this situation, Nagi marries the Princess—partly for the peace treaty, and partly to use her as a hostage should war break out again.