Engagement Annulment Threatens National Survival

On a certain continent, in a certain place, there exists a kingdom that fights monsters day and night. The kingdom is adjacent to a miasmic land that produces monsters, and has been expanding its territory while gradually purifying the miasmic land. Though the kingdom has the advantage in recent times, reading through its long history reveals that it has suddenly fallen into disadvantageous situations more than once, with the miasmic land expanding. Just like this time—an entire battle line can collapse from just a single monster! Upon receiving this report, the prince set out accompanied by the royal guard knights, numbering only about one company. This was to buy time for reorganizing the military... Though the prince is lauded as a magical genius, in his heart he believed he couldn't even buy time. He knew this from fighting monsters many times before—among monsters, there exist aberrations isolated with extraordinary power unlike the others. The front lines have been fortified with such monsters in mind. The prince is not so optimistic as to harbor the arrogance that he could buy time against an aberration that easily collapsed such defenses. Yet knowing this full well, he chose to fight the aberration, willing to stake his life to protect his country. This is a story of such a prince breaking off his engagement. Please, everyone, do not forget the phrase "synopsis fraud," and read on.