Ariadne System

Ariadne System (システム・アリアドネ) was a system built into YGGDRASIL.

Overview
The Ariadne System was a system in the game that checked the validity of a base created by players. Plainly speaking, to build an invincible fortress, one would assume that to do this that the entrance to the base needed to be sealed. Under the Ariadne System, such action was not allowed. To prevent players from making such a base, the Ariadne System ensured that a base must have a path that leads from the entrance to the heart of the base.

Mechanics
Beside insuring an unobstructed pathway exists to the heart of a base, the in-game surveillance system also inspected the distance one could travel inside, how many doors, and rules concerning base constructions that were set in detail. Any dungeons that violated these rules were flagged by the YGGDRASIL system and the guild responsible for said dungeon would fined and have their funds deducted.

The Invaders of the Large Tomb Arc
While observing Nazarick's security system in anticipation of the invading workers, Ainz Ooal Gown with Albedo observed that the Ariadne System had not been triggered. Albedo cautiously asked if the system would be triggered if they manipulated the encroaching humans to do so, to which Ainz stated that there may be a chance where the system won't be triggered, but would be too scar to risk.

Trivia

 * In Greek mythology, Ariadne was a princess that aided the hero Theseus in defeating the Minotaur by giving him a sword and ball of thread which he used to find his way out of the Labyrinth.
 * The Great Tomb of Nazarick circumvented the Ariadne System through the expansion of the 5th and 6th Floors.