The Prafian War was a war between the Yunnaiteddo Federation and the Kingdom of Falglor over the river of Prafia, which had separated their domains for about two centuries at this point. Prafia was a valuable river for multiple reasons. One, it was the established border between Falglor and Yunnaiteddo, so whoever controlled it would gain an advantage over the other. Secondly, it was rich with trade, seeing as the river of Prafia stretched all the way from The Southern Ocean to Uthan, which made it very valuable. The river was never really placed under the control of one side. During the initial revolution that brought the Yunnaiteddo into existence, Prafia was a point of much contention, and the treaty that declared Yunnaiteddo as a sovereign nation did little to actually differentiate whether or not the river belonged to a specific side or not. The two nations would continue to settle on the coast, with several settlements adjacent to each other, just across the river. The initial tension of the rebellion eventually simmered down, but never really faded away.
The whole war started with the death of the leader of one of the northeastern clans, the Shokubai. The death of the leader allowed his son, Gein, to rise to the position of leader. Gein was dropped headfirst into the political climate of the federation, and made some less than wise decisions, one of those being to expand the Shokubai's influence over the river by taxing merchants seeking to enter Uthan to pay off some of the debts the clan owed. This upset a great many of said merchants, a majority of which were Falglorian. These upset Falglorian merchants would then complain to the then King of Falglor, Edward the First. Edward, seeing this as an opportunity to expand his influence westward in the Yunnaiteddo, leaped at this opportunity and demanded the Shokubai cease their taxation at once. This conflict eventually started to spiral further and further until both Falglor and the Shokubai clan were on the verge of open armed conflict.
Gein wasn't necessarily the sharpest knife in the drawer, but even he knew that the Falglor could easily wipe the floor with the Shokubai without a second thought. So, to counteract this, Gein went around to various eastern clans who had a vested interest in the rivere and began asking for assistance, or even an alliance so that they could repel the invaders, eventually forming the Eastern Alliance. The clans, while united against Falglor, were generally mistrustful of each other, each of the combined armies fielded by the Alliance being strictly regimented and divided between the different clans.
The troops fielded by the Eastern Alliance weren't that impressive, mostly comprised of poorly armed peasants who had been forcefully drafted into the army, several Uthani mercenary companies, and the elite Samurai warriors that Yunnaiteddo is so famous for. Their combined defences were lacking, seeing as no one wanted to invite another clan onto their soil to man their forts, leaving most fortifications undermanned. The navy of the Eastern Alliance was comprised of only a very few actual warships, with most of the vessels in the navy being converted merchant ships crewed by impressed sailors or unskilled peasants. The Falglorian army was much more impressive, composed mostly of professional soldiers, cavalry, and battlemages. Their navy was average for the time, having a multitude of warships in multiple ports all across their kingdom. Falglorian and Alliance troops began to gather at the borders of the Prafian River from Stella all the way to Pereo in camps parallel to each other. The stage was set for a war to begin at any moment.
The Falglorians struck first, a force of about 50 or so warships attacking the Prafian estuary, seeking to cut off any potential coastal Alliance reinforcements. They met significant resistance from the local navy, but their superior ships and men overcame them easily at the Battle of Cloven Estuary. The Alliance scrambled to respond, with naval skirmishes erupting throughout the river, and clashes over several bridges. The Falglorian army pushed through Kendriya Bridge, demolishing the opposing Alliance army, and landing Falglorian troops on Yunnaiteddo soil. While the Alliance technically controls much of the Prafian River, their ships are ill-equipped to deal with ground infantry, especially battlemages, who sink Alliance ships before they can even respond in kind.
While the initial assault, with the Falglorian first strike at Cloven Estuary and attacks throughout the bridges overseeing the Prafian River are devastating and inflict serious initial losses and casualties onto the Alliance armies, the Falglorian army soon finds that the population is against their invasion, making it hard for them to hold the already conquered territory, much lest invade more of the Alliance. See, Edward, and most of the Falglorian Royal Family hold irredentist beliefs. Edward's main goal for this war is to not only establish sovereignty over the Prafian River, but to also establish a foothold in mainland Yunnaiteddo, annexing the entire Shokubai clan and perhaps even more. Not only that, but the war is designed to weaken the federation as a whole to serve as a prelude before an entire Falglorian invasion of the entire nation.
When the Falglorian army trounced the initial Alliance defences on the river, the first Alliance general in charge of the combined armies of the Alliance had embarrassed himself when he attempted to lead a brave charge of about 50 Samurai against the fortified positions of a Falglorian camp, before the small strike force were slaughtered with hails of arrows and fireballs. The general had survived, but because of this frankly stupid charge, and the fact that it was outed that he was only appointed general because of a few bribes and the fact that he was the son of an influential clan leader. He was promptly discharged from the position, and the role of general was up for grabs, which was just as well, seeing as the Alliance would need a competent military leader if they were to push back the frontline to beyond the Prafian River and turn the tide of the war.
In the coming days, a new figure that was a perfect fit for general emerged. The Spirit Warrior at the time, Deusu Makina, a low-ranking first cousin in the Ekusu clan who had gained minor attention from his attainment of the title of Spirit Warrior had joined the army voluntarily, and was quickly made the leader of the Ekusu division of the Alliance army, quickly being propelled into fame for his victory at the battle of Karamiatta Forest, ambushing a larger Falglorian force and winning with relatively low casualties, and pushing the Falglorians out of the Ekusu domain. Because of his noble-born status, his military success, and popularity among the troops, the different clan leaders of the Alliance convened on Augurim the 18th and officially made Deusu impromptu leader of the army.
Deusu immediately began to produce effects, modernizing and improving the alliance army, equipping the peasant infantry with better equipment, such as actual armor and weapons, along with utilizing cavalry to a much higher degree. One of the more influential decisions made by Deusu was to equip a great many of the infantry with crossbows. Crossbows, despite being weaker and taking longer to load than bows, can easily be used by soldiers, and it only takes a short time for soldiers to learn how to effectively use, meaning that great quantities of peasant crossbowmen could be trained and fielded in not a lot of time. While Falglorian bowmen were typically much more accurate, fast firing, and all around better than the Yunnaiteddo crossbowmen, they were outdone by the sheer volume of crossbowmen. The alliance were able to get these large amounts of crossbows from Uthan, who sold and lent crossbows to the alliance at a high cost.
Operations were immediately conducted against the occupying Falglorian troops and fortifications. Raids against supply centers, ambushes on marching columns, and night time attacks against forts. The Falglorian army found their position untenable, and began to withdraw from Yunnaiteddo, opting to hold their positions near bridges. The alliance's goal was to push through the Falglorian defences, take the river and the bridges, retake Cloven Estuary and then finally take Flumen, and important city on the edge of the Prafian River which also serves as the army's main base of operations in order to finally convince Falglor to surrender.
Falglor's plan is basically the same, except when they got pushed out of Shobukai, their plans were changed a bit. Now their strategy is to convince the western clans that now is the perfect time to seize glory and attack the Eastern Alliance, pinning the alliance between Falglor and the western clans, forcing them to sue for peace, allowing Falglor to have a foothold in Yunnaiteddo for future wars and to control the Prafian River. While their withdrawl from the territory of the Shokubai clan was a serious setback, they still controlled most of the Prafian River and had a great advantage over the Alliance army.
Falglorian naval commanders, expecting a Yunnaiteddo counterattack at some point, gathered their forces around Cloven Estuary. However, instead of attacking the fleet around Cloven Estuary in an attempt (that most likely would've ended in failure) to control sea access to the Prafian River, Deusu decided to cause a nearby mountain to collapse, creating a dam between the ocean and the river, completely cutting off most of the fleet outside the estuary. While it could be possible for Falglorian troops to remove the dam, it would take valuable time, manpower, and resources.
Just a day after the damming of the Prafian River, the alliance army would push out in a three pronged attack against three bridges, causing one Falglorian army to be pushed back across the river. Using this, the succeeding army would then split in two and flank behind the other two Falglorian forces, causing them to be stuck between hammer and anvil. Using this momentum, the alliance army would turn to Flumen, and began to besiege the city. Flumen was ill-prepared for a siege, believing that any potential assault was either impossible or far-off, and as such, they were caught off guard, and their siege lasted about two days before they gave up.
With Flumen in their hands and the Prafian River under their command, the Alliance told the king to surrender. While Edward typically wouldn't, a few factors were pushing him to. The Ravenna Revolt had been occurring, causing a drain on their resources and their economy. The people were also beginning to grow tired of the Prafian War, with only a few hardcore river merchants urging Falglor to continue on with the war. As such, Edward was forced to come to the negotiating table. Falgor would concede it's claim on the Prafian River, and the Alliance would pay a fair bit of reparations.
Consequences
Because of the war, the eastern clans of the federation, especially the Shobukai clan, would fall into a deep debt to Uthan for war materials and mercenaries, one that would not be paid off until the Blood War. The political landscape of Yunnaiteddo would be shaped by the Prafian War for a great many years to come. Falglor, the losers of the war, were heavily embarrassed, their military might was put into question, and Edward became deeply unpopular. The Prafian War might have also directly lead to the Eastern Adhyrianus War and the conquest of Adhyria.