Nobunaga’s Imouto is My Wife

The male student, Fukai Nagamasa, ignores his studies for college entrance exams in favor of following the path to chuunibyou. As he fainted during night cramming session before the exams, he realized that he was transported to a parallel world as a feudal lord in the Sengoku Era. Not to mention that suddenly, he was marrying the sixth Demon King, Oda Nobunaga’s little sister, the one who was purported to be an unrivaled beauty?