*Beastmen and humans have a long history of mutual hostility. Until 20 years ago, humans killed beastmen, skinned them, stole their Beast Stones, and used them as slaves. Furthermore, mages drove beastmen to the brink of extinction. A war raged for 10 years, resulting in 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 gem possessed only by beastmen, with only one per individual. It grants the beastman their unique power. It is incredibly beautiful and sparkling, located next to the heart (highly coveted by humans).

Mage: Occurs only among humans and is extremely rare. A powerful Archmage is nearly invincible.

Beastman: Stronger and physically tougher than humans. They possess unique powers originating from their Beast Stone. If a gem called a Suppression Stone touches their body, the Beast Stone causes intense 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 ends up marrying the Princess, both for the sake of the peace treaty and to use her as a hostage in case war breaks out again.