The story so far—

In the Belgarian Empire, there lives a girl named Marie Quatre Argentina de Belgaria—“Altina” for short—who happens to be the fourth in line to the imperial throne. She is a princess who, at a mere fourteen years of age, resolved to fix the corruption plaguing her nation.

“I’m going to become empress,” she tells Regis Aurick. “I need your wisdom.”

Now, Regis is inept with a sword, unable to ride a horse, and apathetic toward the empire he serves. He is a hopeless soldier by all definitions who spends his days buried in books, yet she still enlists him to be her tactician.

Through a duel with the hero Jerome, a battle against barbarians, and the capture of the impregnable Fort Volks, Altina steadily raises a formidable military force.

Conscious of the fourth princess’s achievements, Latrielle invites her to the capital to join the celebration commemorating the founding of the nation. But as the Belgarian Empire shakes under the weight of a vicious power struggle, High Britannia declares an all-out war.

Coinciding with this sudden invasion, the Grand Duchy of Varden launches an attack on Fort Volks. Regis’s scheme sends them running in a single night, however, and a month later, he finds himself assisting the Seventh Army’s retreat in the Battle of La Frenge.

Regis then manages to defy the odds on the western front. Serving as admiral proxy, he leads the Western Liberation Fleet to a swift victory, managing to take out the enemy fleet. From there, he immediately leads the Empire’s Fourth Army to rout the last supply shipment under the protection of the infamous Mercenary King.

And so, the Belgarian Army puts a stop to the High Britannian invasion. Latrielle returns to the imperial palace to deliver the news, but the behavior he witnesses is completely unbefitting of a nation-threatening crisis. The emperor spends his time indulging in pleasures, and upon seeing him succumb to such depravity, the prince’s anger finally reaches breaking point. His hand moves to his treasured sword, the Armée Victoire Volonté...

The cause of the emperor’s death is of course falsified: he is announced to have died of old age.

The fleeing High Britannian Army joins forces with the Kingdom of Langobarti, and together they capture the fortified city of Grebeauvoir to the north. At Latrielle’s request, Regis joins the First Army in its campaign to recapture the stolen territory.

Through another of Regis’s plans, Third-Grade Combat Officer Varèse manages to infiltrate the captured city. There, he gains the cooperation of a girl named Fel and succeeds in freeing the civilians held captive there.

In the decisive battle, Latrielle entrusted Regis with command of the First Army. The tactician is quickly able to overwhelm the Langobart Army using the knowledge he has gained not just from books, but also from his personal experiences. With a large-scale trap, he floods Grebeauvoir and forces those in the city to surrender.

As the battle reaches its end, the movements of the enemy army suggest its commander has fled. Latrielle personally leads the charge, at last forcing the High Britannian queen into a corner. Oswald, the enemy commander, attempts to recover from his hopeless position with a one-on-one duel, yet he quickly falls to the prince’s sword.

The war finally comes to an end, and the Empire is victorious...but Latrielle now knows just how much of a threat Regis’s wisdom poses to his reign. It is with this knowledge that he makes a solemn declaration:

“Kill Regis d’Aurick.”

The knights of the Empire’s First Army draw their swords, but little do they know, another assailant has already appeared before the tactician.