The awakening of princess Ryuu

A girl of age 16....(not just any normal girl!!^~^) Im speaking.......
She was the princess of a land. So weak. So when enemies came. Her brother and father went to fight. But their army was weak. Her father soon perished because of the war and her mother died because of her illness from the constant worrying of her husband. Her brother decided to make a demon blade.....the ryuuga. However...he did not know that the sacrafice was his sister. He rejected the fate of his sister dying and went to battle. No sooner, he perished as well. The sister was so sad,she made herself the sacrafice for the demon sword. Thus living in it for a thousand years slumbering. Becoming a demon. The demoness of Ryuuga.