Kurotsuki no Yaergnacht

While on his way home from an interview, unemployed, unmotivated, jaded 18-year-old Inumata Shinogi encounters the beautiful lady and evil spirit Yaergnacht Finsternnis. She demands him to either marry her or die on the spot. He must command the battle against enemies of humanityーthe apostles of god (Highlander), and save the world with his wife!! Battle fantasy with the infatuated strongest kuudere beauty, start!

(Source: Kodansha, translated)