In the Kanuchi series:

V.1 - Shiroki Tsubasa no Shou

2000 years ago, Naotsu country. There are two families in power, the Takamahara house and the Yasuna house, who are always fighting. Yasuna house's son Izusami and Takamahara house's daughter Kayana fall in forbidden love. In the final battle of the war, the white-winged Kayana confronted the black-winged Izusami, and Izusami was killed. Thus the war ended, and Kayana took the throne. But, her pure white wings turned jet black...
2000 years later, in Takamahara country, where such a myth remains, an accident occurs involving a girl named Aki... More...

In the Kanuchi series:

V.1 - Shiroki Tsubasa no Shou

2000 years ago, Naotsu country. There are two families in power, the Takamahara house and the Yasuna house, who are always fighting. Yasuna house's son Izusami and Takamahara house's daughter Kayana fall in forbidden love. In the final battle of the war, the white-winged Kayana confronted the black-winged Izusami, and Izusami was killed. Thus the war ended, and Kayana took the throne. But, her pure white wings turned jet black...
2000 years later, in Takamahara country, where such a myth remains, an accident occurs involving a girl named Aki...

Vol.2 - Kuroki Tsubasa no Shou Less...