High School DxD, Vol. 6 (light novel)

Years ago, Asia healed the wounds of a demon by using her Sacred Gear. When the
Church learned of it, she was excommunicated from the organization that had been her
entire world. Now, that same demon, Diodora, has returned, hoping to marry
Asia. Only defeat in a Rating Game can stop him, but could there be more to the
gentle-looking demon Asia rescued from death than first believed?