Ru is a vampire. Wreaking havoc in a certain remote kingdom, she decided to escape from persecution to a place with the romantic name "Forest of Death", where no one would have found her for sure. Having stumbled upon the settlement of Hiraku Matio there, she was detained by his vigilant wolf guards. As a result, she stayed to live with Hiraku, helping the development of the village with charms and alchemy.
She became Hiraku's first legitimate wife and gave birth to his son.
