Roble Holy Kingdom

Roble Holy Kingdom (ローブル聖王国) or more commonly referred to as the Holy Kingdom is a human nation which occupied the peninsula located southwest of the Re-Estize Kingdom.

Background
The Holy Kingdom as it is simply called, is marked haphazardly on maps of the New World. Because of that, there were two special features about the Holy Kingdom’s geography. The first was that its land was divided into north and south halves by the sea, but the halves were not completely separated. Rather, a gigantic bay -- four kilometers long and two and a half kilometers wide -- made its geography look like a U turned on its side.

Reasonably so, some people called them the Northern and Southern Holy Kingdoms due to their nation's geography situated in the New World's map. Additionally, the entrance to the peninsula also sported a great wall, over one hundred kilometers long. It was built to withstand invasions from the massed demihuman tribes which occupied the hills to the east of the Holy Kingdom, between them and the Theocracy.

Their neighboring area moreover, the Wilderness, is inhabited by numerous demi-human tribes who are constantly warring with one another. Not only to withstand the invasion, but the Holy Kingdom uses it to protect themselves from getting caught into the demi-humans' conflict outside their country's border. For that reason, the 10,000 Mile Great Wall was also created with the sole purpose of keeping the savage tribes from encroaching further into their country's mainland. This grand wall, built through the expenditure of a great deal of time and resources, was a silent testimony to how aggravating the existence of the demihumans were to the Holy Kingdom.

While so, the Holy Kingdom’s defensive lines was made up of three linked walls. There were only three fortified gates along the full length of the wall, which was in excess of one hundred kilometers long. They also functioned as garrisons to dispatch troops to the surrounding strongpoints. If the demihumans invaded and an overall mobilization order was given, they would become staging areas where the troops would gather in order to attack the enemy.

Despite all of this, the people and country have always remained vigilante of the constant danger and the nation still suffers from attacks from time to time. In the Holy Kingdom’s history, after the construction of the wall, the gravest invasion of their lands had come during an invasion which took place during the time known as the Long Rain. It was a type of night attack instigated by a race called the Srush scaled the wall and headed deep west into their territory, resulting the loss of several villages as well as a sheer number of its forces before driving them back.

While the massive wall may be incredible in size for human beings, it was no threat whatsoever to races who were several times taller than humans or who possessed the ability of flight. Due to the wall's own weaknesses, there was no way for them to rest easy when faced by demihumans and their many special abilities, even with such sturdy fortifications.

On the other hand, the Holy Kingdom's national hero is said to be a Valkyrie Knight, wielding the Sacred Blade.

The Lizard Man Heroes Arc
Ainz explains to Albedo in great details about the geography of the Holy Kingdom and it having a wall used to prevent demi-human tribes from encroaching into their territory.

The Men in the Kingdom Arc
It was around this time that Demiurge had already starting preparations to initiate Operation Gehenna in the Holy Kingdom, however, due to certain circumstances he had to initiate it in the Re-Estize Capital.

The Invaders of the Large Tomb Arc
While comparing the strengths of all the leading swordsmen in the lands, the Holy Kingdom's Valkyrie Knight was mentioned by the workers.

The Ruler of Conspiracy Arc
After the massacre at Katze Plains and the establishment of the Sorcerer Kingdom, Demiurge was assigned a mission within the Holy Kingdom for what purpose is still not clear.

The Craftsman of Dwarf Arc
After Ainz finished his business in the Dwarf Kingdom, Demiurge began to set his plans for the Holy Kingdom into motion.

Politics
It was a highly religious country, led by a Holy Queen, Calca Bessarez who could use divine magic and who was closely affiliated with the churches. That said, they were not as religiously-oriented as the Slane Theocracy.

Military Strength
Due to dangers from the demi-humans that live in the Abelion Hills are a constant threat to their nation, the Holy Kingdom built the wall which is patrolled by several units. However, due to the limited population of the country and the large scale to monitor it, the Holy Kingdom's military conscript their citizens when they reach a minimum age to join. In other words, the citizens of the Holy Kingdom were conscripted as a form of national service. Nearly anyone who was at least an adult, a citizen of this country, and both male or female capable of handling military duty must take part in their country's affair militarily.

Thus, they would become soldiers and need to spend a certain amount of time being trained, after which they would be assigned to sentry duty on the wall. If the worst were to happen such as the wall being breached, it was even made possible by the former Holy King of the nation to result in mobilizing the entire nation as a drastic response against incoming invaders. The hope was that the country's own citizens would become the manpower with which to protect their land in case the demihumans by chance crossed over the wall.

Although they wanted to fully man the wall in order to prevent an event like the Long Rain from ever happening again, stationing troops at every single point along its length would strain the nation. Instead, they came up with a viable solution which was to build outposts at fixed intervals along the walls. These strongpoints would then be overseen by gigantic fortresses. They stationed a small number of troops in these bases, their purpose being to fight for extended periods, to the last man.

If they managed to encounter an enemy attack however, they would first launch flares to request reinforcements. In addition, there were companies of soldiers who would staff and patrol the fortresses, serving as reserve troops during emergencies, to be deployed as the situation required. After putting these measures into practice, the demihumans weren't able to penetrate the wall again for now.

With great support, all village residences of a certain size were also fortified. This gave the local villagers enough fighting power to hold out until the regular army could arrive, and allowed said villages to serve as military outposts.
 * Nine Colors

Trivia

 * In the Web Novel, it is stated that the Holy Kingdom have once maintained connections with the Slane Theocracy, but due to the encroaching warring demi-human tribes, the latter lost contact.
 * Demiurge was sent to the area and collected the skins necessary to produce magic scrolls.
 * The Great Wall here could be a reference to the Great Wall of China, built to keep out the Huns.
 * While normal Human skin can only be used to create scrolls that contain magic in the first tier, the skin from humans in the Holy Kingdom can create scrolls that can hold up to the third tier.
 * The villages of the Holy Kingdom were far better protected than those of other countries, and they could also function as military bases.