Highschool DxD: Love and War

Summary Issei's childhood bestfriend, Higurashi Otome moved in America for a year. During their middle school years, She was oblivious that Issei had a crush on her but apparently only likes Issei as a brother. One year later, she returned in Japan and wants to surprise Issei for her return. Otome noticed that Japan feels different than before. What mysteries and adventures lies ahead? Will she find out about her true identity?