Abelion Hills

Aberion Hills (アベリオン丘陵) is an area patch of wilderness with vast hills that lies right between the borders of the Slane Theocracy and the Roble Holy Kingdom.

Background
In the past, this area was home to a kingdom of hill dwarfs, but it was destroyed by demi-humans. Currently, it is a lawless area where a myriad of demi-human tribes fight day and night for control. The constant warfare and dangers these demi-human races produce is so troubling that the Roble Holy Kingdom constructed the largest and longest wall barrier on the continent to keep them out. The Slane Theocracy have made ​​numerous attempts to subjugate and cleanse the area, but so far its efforts have only managed to temporarily thin the demi-human population.

In the past, the Adventurer's Guild of the Kingdom had sent people there, but none have ever returned in one piece. As a result the area is completely unknown terrain to the kingdom's citizen.

The Ruler of Conspiracy Arc
As part of Ainz's persuasion to get Ainzach to trust him in turning the Adventurer's Guild from a mercenary group to real adventurers to explore the unknown and new lands. Ainz used the Aberion Hills as an example of what sort of potential exploring new lands would mean to the Adventurers.

Ainz also spoke of providing support and assistance to all guild members if they would agree with his new reforms and is also seeking to use their help with finding more detailed information of the people that live there and what opportunities the land itself could provide.

Ainz also mentioned that the Sorcerer Kingdom is making preparations for any potential future conquest, however only once that available information is procured and assured that he will not involve the Guild in their subjugation.

Layout
The area consists mostly a patch of wilderness that consists of mostly hills and wild forests. It's borders make up of mountain ranges in the south, north and east regions and by the Great Wall of the Roble Holy Kingdom in the west.

Known Inhabitants
The Aberion Hills is home to various demi-human tribes such as dark dwarves, goblins, ogres and orcs.

Trivia

 * The Aberion Hills are only presented in the Web Novel while the Light Novel didn't state its name.
 * Metal appears to be scarce in the area and is a commodity that the local tribes quarrel over.