Seirei Gensouki: Spirit Chronicles Volume 16

After successfully escaping an ambush in the Rubia Kingdom, Rio escorts Beltrum's royal sisters to the Galarc Castle, where he is given a place of residence for his repeated achievements. However, an investigation over a series of unsettling, cross-kingdom incidents continues to complicate matters.
But in a stunning turn of events, with Princess Charlotte's affections now directed at Rio, will our fateful knight be able to weather the storm of love that is brewing?