The Reincarnated Prince and the Hero of Light — Nobiru Kusunoki

Some years have passed since the otaku spinster, Ryoko Hayakawa, was reincarnated as the Seventh Prince of Gracis, Herscherik. As Herscherik approaches his seventh spring, his campaign to save his kingdom faces an unprecedented challenge -- the Atrad Empire has taken advantage of the unrest in Gracis to launch an attack. At the same time, Herscherik's arch enemy, Prime Minister Barbosse, sets another one of his evil schemes in motion. Having failed at both assassinating the prince and winning him over, the minister has yet more dangerous machinations in store for Prince Herscherik and his men...