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 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. Their neighboring area, the Wilderness, is inhabited by numerous demi-human tribes who are constantly warring with one another. The country’s border is protected by a wall, the 10,000 Mile Great Wall, keeping the savage tribes from encroaching.

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. The most severe of these was during the time known as the Long Rain. A race known as 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.

The 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 Demiruge 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 the ever dangers from the demi-humans that live in the Abelion Hills are a constant danger, 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 certain age. Nearly anyone both male and female who is capable of military duty is given training and is required to serve the patrol at least for a specific amount of time.

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.