Seirei Gensouki: Spirit Chronicles

Rio returns home to the village of the People of the Spirits. The next day, he wakes to find an unknown, beautiful, naked girl beside him...?! Latifa and the others peek into the room and chaos ensues, but it turns out that the girl is Rio's bond spirit. As she doesn't have a name, Rio gives her one-Aishia. Dryas, a spirit of great trees, appears after sensing the presence of a powerful spirit. At her urging, Rio and Aishia agree to fight in order to determine her combat capabilities.