The Man Made Dungeon Knossos (人造迷宮クノッソス), more commonly known as Knossos (クノッソス), is an artificial underground labyrinth which connects the dungeon and Daedalus Street, effectively serving as a second entrance to the dungeon.
Knossos' creation began with Daedalus after he was captivated by the original dungeon. His descendants, including Dix, were forced to carry on this project by their blood, which Dix referred to as a "blood curse". The labyrinth also acted as Evilus' secret lair during Orario's Dark Era and the period following the organization's downfall.
Aspiring to surpass the real dungeon, Knossos was built with a variety of the highest quality materials to maximize its defensive capabilities as much as possible. Its composition has turned the place into a virtually impenetrable fortress either through physical or magical attacks, making it impossible to break into it. On the other hand, its dimensions are truly colossal, each floor being the size of the entirety of Orario.
Being a labyrinth, Knossos is composed of multiple intricate paths. As soon as one enters the site the trail quickly divides into multiple dizzying directions. Having several forks and four-way crossings makes the number of possible roads to take countless, with a wide variety of them only leading to dead ends. Although its structure is typical of a labyrinth, its complexity is extremely high, easily surpassing that of the Daedalus Street, a place famous for being impossible to escape once one becomes lost in it.
Its corridors have magic-stone lamps that illuminate the area and are quite wide, their width being enough to allow three Dwarves to walk comfortably side by side. As a result of its great antiquity, there are several cracks that run along the entire length of the complex. Still, the walls look strong and durable, with no hint of potential collapse, thanks to detailed planning and meticulous construction.
Furthermore, in order to act as one more impediment to prevent the conquest of Knossos, there are gates located throughout the complex, stopping any possible progress. The doors are made of Orichalcum, the strongest material in the world, so penetrating them is an impossible task. These doors typically can only be opened by either the eyes of the descendants of Daedalus, or a key called a Daedalus Orb made from said eyes, as they emit a specific magic frequency that allows the activation of all the mechanisms within Knossos. However, a user of the Mystery development ability can craft an item that replicates the magic frequency. This is quite complicated, though, requiring in the first instance to have a Daedalus Orb to study the frequency, as well as to have multiple drop items to be able to create it, in addition to a great mastery in the area of the manufacture of items. An expert like Asfi took ten whole days to produce a single replica.
Although one might think about going through the walls to circumvent this problem, it is not a viable option. All the walls were made using exclusively adamantite, the second material with the highest resistance known to man, extracted from the Deep Floors, the highest purity and therefore of the best quality that can be obtained, turning the breaking of a wall into an arduous task achievable only by very few first class adventurers.
According to Ottar, a person would need to be Level 6 or higher to be able to break pure adamantite, a fact demonstrated when of all the first exploration group of the Loki Familia only Gareth, a high Level 6 specialized in strength, was capable of breaking a wall and dig a hole large enough to allow a person to pass through. Even then, the feat left Gareth's fists badly injured, with him pointing out that it was not a plausible alternative they could use frequently. Thanks to this, the walls force everyone to follow the preset passages.
Additionally, the walls are completely covered by a special black stone. Although it does not have a particularly high hardness, as it can be effortlessly broken and removed with a simple blow, it was made from Obsidian Soldier's Body Stone, giving it anti-magical properties that severely reduce the power of any spell, serving as a countermeasure against any offensive spell. Even Riveria, the most powerful mage in the world, recognized that she could not create an opening.
Although the descendants of Daedalus follow the original idea of their ancestor to the letter and with millimeter precision there have been two instances in which Knossos has received expansions that were not part of the original schemes.
One of the implementations was at the hands of the Creatures after Evilus allied with them and Enyo to destroy Orario. In spite of Barca being initially opposed to the idea, he ended up giving in. The addition consisted of a stone pedestal similar to a tree stump covered in layers of ivy with which it is practically fused. Above it is a watery blue-white veil with a red jewel, similar to the ones on the doors but larger, inlaid in front of it. The device is the most important of all Knossos and only the descendants of Daedalus are capable of operating it.
The device allows them to freely control the doors of the labyrinth from afar, requiring only that the user places their hand on the jewel so that immediately afterwards, after a brief simultaneous glow of the jewel and the user's eye, the desired door or trap is closed or open. Scattered across the entire site, there are reliefs and multiple demonic-looking statues in the hallways, which serve as surveillance cameras, mirroring the scene before them on the pedestal. This allows to quickly and easily get rid of unwanted intruders or lock them in a corridor to set up ambushes.
The second modification came at the hands of Dix, born out of his hatred for Knossos itself. In one of the deepest and most intricate parts of all the labyrinth is located in a huge circular room with four entrances, similar to an auditorium, another pedestal also with a large red orb. While it is similar to the previous one, its function is completely different. By rotating the orb in a specific pattern and pressing it, it is possible to select a floor on which, after activating the mechanism, all supporting pillars will be destroyed, causing the entire floor to collapse. The destruction can be used offensively to take down an overwhelming number of enemies. However, this in turn would cause severe and unimaginable damage to Knossos, as it was its original purpose, greatly delaying its completion.
Through the entire place there are several square rooms of various sizes, although all are spacious, with the smallest having measurements of around 50 meters and the largest being able to house monsters the size of Floor Bosses, dozens of adventurers and, even then, still have enough free space for them to be separated from each other by a considerable distance.
Since it used to be Evilus's lair, some rooms were used for different functions. One of them, located on the ninth floor, served as Evilus's main base while others, located on the tenth floor, were the home of the Demi Spirits prior to their defeat against the adventurers of Orario. Finally, on the eleventh floor, there was one that was the resting place of the Nidhogg raised by Enyo.
Despite being under constant construction for a thousand years, the man made dungeon is still not even close to being finished. The structure reaches the Middle Floors, barely fulfilling 30% of the plans originally made by Daedalus. The work is incomplete not only in the floors that have yet to be developed but also in those already built, being possible to see holes of different sizes in some areas where expansion still needs to be done.