She's the Strongest Bride, But I'm Stronger in Night Battles GN VOL #1

(W) Singyougaku

(A) Arinokamati

In this Mature-rated isekai manga, an ordinary man becomes a military genius and the hottest lover in the realm-in another world!
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!