Yasashii Ryuu no Koroshikata Manga

In a world divided between humans and mythical beasts, two clans once ended their endless war by pledging to live apart. The king of the beasts gave his sword to the human queen he loved, promising that he and his descendants would come to her or her descendants’ aid if danger ever threatened them. As a third war approaches, a beautiful swordsman who carries the blood of the beast king has a fateful encounter with the aloof king of the mythical beasts. Their meeting begins a story shaped by the old pledge and the conflict between their peoples.