Battle's Bride2005

In this spicy isekai, an ordinary man becomes a military genius and the hottest lover in the realm-in another world--part of Seven Seas' Ghost Ship imprint! Compelled to marry a royal demoness and put to work--on the battlefield, and in her bedroom--Albert finds his new life in another world anything but peaceful. Yet thanks to his knowledge of Earth's history, Albert is able to launch a revolution, and is having a ball doing it alongside his sexy demon bride!