The Abyss

"The allure of the Abyss is inescapable. Even so, no one has managed to reach the end. A golden city that sleeps at the bottom of the Abyss. Relics that surpass understanding. For 1,900 years, we have ventured into the darkness hoping to make greater and greater discoveries. The romance of a lost age and the arcane. Drawn to the great unknown, the Abyss devours us."

The Abyss is a colossal pit discovered 1,900 years ago around the islands of the southern ocean of Beoluska. The vertical hole with an opening diameter of around 1,000 meters and speculated to be over 20,000 meters deep. It possesses a unique ecosystem, wherein lie the remnants of an ancient, yet advanced, civilization. Many have challenged the mysterious Abyss, pursuing countless hidden treasures and relics of immense value. Some are treasure hunters looking for Artifacts, while others are explorers determined to unveil the secrets the Abyss hides. To explore the Abyss, valiant cave raiders called Delvers emerged, and the town of Orth was established at the edge of the Abyss.

The Abyss still contains many sections that have never been seen, and carries many dangers. Hazardous habitats that defy common sense and otherworldly creatures adapted to the unique environment are major obstacles to explorers.

All over the Abyss, there is a mysterious force field which Nanachi refers to as the "very blood of the Abyss, so to speak". The force field acts as its main source of energy, sustaining life by carrying sunlight and nutrients down into the depths where it would otherwise be impossible for light to reach. While it is present everywhere, it seems to be more prominent the closer one gets to the center of the vertical shaft. More savage and dangerous creatures are often found in areas where the force field is most prevalent, and the branches of vegetation always point towards the center of the hole, their main source of energy for undergoing photosynthesis. Delvers use this fact to guide themselves when they are lost. The force field itself is invisible to the naked eye, but it can be detected as a vague fog that limits the vision of humans. The field is also constantly moving, following the movements of living beings to the point of breathing being enough to change its flow, and altering its flow as it responds to their consciousness. There are a few specific spots in the Abyss, usually far away from the center and in secluded areas, where the force field doesn't exist or is extremely weak.

The great pit also appears to have some form of time distortion. This is evidenced by Ganja having arrived at the Abyss at a point in time before the first Delvers and a native tribe still existed, yet, according to Wazukyan, only 150 years have passed since the creation of The Village of Iruburu in the 6th Layer. The White Whistle Delver Ozen claims that the deeper one delves, the more one's sense of time breaks, with the effect becoming extreme from the 5th layer onwards. As an example, she noted people might intend to stay on the 5th layer just a few weeks, but by the time they return to the surface, several months had passed. As such, Ozen considers it a possibility a decade on the surface may be akin to a few years on the bottom of the Abyss.

The Curse of the Abyss
Though the Abyss is riddled with countless dangers and hazards, one of the greatest challenges facing Delvers is, in fact, the ascent from it. This is due to a phenomenon called the Curse of the Abyss. The term refers to a series of symptoms that manifest upon ascending while inside the Abyss, with its more scientific name being the "Strains of Ascension". The effects of the Curse manifest after ascending around 10 meters within the Abyss, with no way to avoid it through conventional means. The Curse affects all living things; however, their symptoms may differ from those appearing on humans depending on how close the creature resembles a human.

The deeper one delves, the more severe the symptoms are, starting at mild dizziness and nausea and gradually rising to intense pain throughout the body, loss of senses and even death. This makes the return trip from the Abyss extremely difficult, and it is not uncommon for Delvers to perish on the way up. Particularly, the curse of the 6th Layer ("loss of humanity and in some cases death") makes the return journey physically impossible for humans.

The Curse results from piercing the force field of the Abyss while ascending, although this fact is not generally known. With Layer piled upon Layer, the force field blankets living beings similar to cloth warping around them. Its flow is similar to inverted thorns, allowing one to pass through in descent, but being harmful when trying to ascend.

Areas where the force field is weaker also result in the effects of the curse being less severe. In certain specific places, like Nanachi's hideout and The Village of Iruburu, the force field isn't present at all, and so the Curse doesn't occur either.

Rare Phenomenon

 * Birthday Death Disease

As the mind comes under attack in the depths of the abyss, the effects gradually show up physically too. This effect doesn't show up immediately like the curse of the 6th layer but over time, treading the boundary of sanity, life and death the skin of the head becomes twisted. Notably, enduring the effects of the curse of the 5th Layer can begin to show these effects even after a couple of times.
 * Abyssal Hair Twist

The Abyssal Hair Twist can be a quick indication that someone has challenged the far depths of the Abyss.

The Blessing of the Abyss
An exceedingly rare and top secret phenomenon occasionally takes place within the Abyss under very specific circumstances. It was first discovered by the White Whistle Delver Bondrewd when he was experimenting with the Curse of the 6th layer. Much like with the Curse of the Abyss, the event occurs during the ascent, but two people are needed to trigger the phenomenon. If one person bears the entire burden of the Curse for both people (through the use of an Artifact or another similar instrument), the other is spared the effects of the curse.

Bondrewd modified several Artifacts to create an elevator to observe the Blessing phenomenon. This two-chambered elevator carries two people but forces the entire weight of the Curse onto a single person. If the person receiving the Curse doesn't die midway through, the other is spared the Curse's effects. Bondrewd discovered deep love between the two people results in the event he called a "Blessing" for the one who does not receive the burden of the Curse. While the Blessing was experimentally demonstrated, Bondrewd cannot explain the reasons behind it.

The appearance of the blessed changes. They grow fur all over their body and some of their traits, like the eyes or fingers, become mutated. The Blessing is not merely in looks: The one gifted gains the ability to observe the force field of the Abyss, something that only the predators of the deep are able to see, and is an incredibly useful ability for delving in the pit. It also appears to increase their physical fortitude to some extent. Another side-effect of the blessing appears to be the fulfillment of a desire, as shown by Nanachi obtaining a body that smells particularly nice.

Abyss Faith
A religion that was formed around the Abyss itself, it appears to be a very common belief among those that delve into the Abyss. Instead of believing in a God, those that turn to this religion deify the Abyss itself. Because the bottom is unknown, it replaces a deity and grants them hope for an after-life. It is based on the principle that if one loses one's life within the Abyss, one's soul will depart on a journey to someone who has wished for life. The unreachable depths of the pit makes people believe that it transcends life itself.

1st Layer: Edge of the Abyss

 * Depth: 0~1,350 meters.


 * Strains of Ascent: Light dizziness and nausea.


 * Description: The 1st layer is the most shallow section of the Abyss, right below the town of Orth. The environment is consistent and sunny, full of hollows in the grassy rock faces and petrified trees. The wildlife consists of fantastical and mostly harmless animals. Scattered and hidden all across the 1st layer are Praying Skeletons.

2nd Layer: Forest of Temptation

 * Depth: 1,350~2,600 meters.


 * Strains of Ascent: Intense nausea, headaches, and numbness of limbs.


 * Description: The Forest of Temptation is the first truly dangerous section of the Abyss. The fauna and environment suddenly change, turning into a tropical rainforest with huge vegetation. The creatures that inhabit this layer are much more dangerous. Deeper in, there is an area, known as the "Inverted Forest", where the trees grow upside-down, the updraft wind blows hard, and even water flows upward. An Observation Camp has been built here to serve as a resting point for Delvers.

3rd Layer: Great Fault

 * Depth: 2,600~7,000 meters.


 * Strains of Ascent: In addition to aforementioned effects, Vertigo combined with visual and auditory hallucinations.


 * Description: The 3rd layer consists of a 4-km vertical cliff, making it a highly challenging area to cross, save for the large cave network around the main shaft. Countless methods have been implemented by many in order to attempt a descent, to varying effects. Aerial predators are common, including Crimson Splitjaws.

4th Layer: The Goblets of Giants

 * Depth: 7,000~12,000 meters.


 * Strains of Ascent: Intense pain throughout the body and bleeding from every orifice.


 * Description: A strange, humid jungle of strong vines weaving to form giant concave discs that capture water from the air, which are what earn the 4th layer its name, the "Goblets of Giants." At 9,000 meters marks the famous Garden of the Flowers of Resilience, an area filled with Eternal Fortunes, the trademark flower of the Abyss. A truly beautiful sight; though the danger from the beasts that dwell here is high.

5th Layer: Sea of Corpses

 * Depth: 12,000~13,000 meters.


 * Strains of Ascent: Complete sensory deprivation, confusion and self-harming behavior.


 * Description: The thinnest layer of the Abyss vertically, being only 1,000 meters deep, but the widest one horizontally, probably around 10 times wider than the town of Orth. It consists mostly of a large, monster-filled sea with some crystallized sections, held up by a thick layer of dense mud. This is the last layer of the Abyss where it is possible to bear the Curse and return alive and intact. An ancient ritual site turned into a lab by Bondrewd and his crew, Ido Front, acts as a gateway into the 6th layer, the point of no return.

6th Layer: The Capital of the Unreturned

 * Depth: 13,000~15,500 meters.


 * Strains of Ascent: Loss of humanity or death, or under specific conditions, the Blessing.


 * Description: A White Whistle's last dive. A human who tries to ascend from the 6th layer either succumbs to death, or is deformed beyond recognition, hence the name, "The Capital of the Unreturned." In Orth, there is a rumor about a Golden City at the bottom of the Abyss, which originated from the 6th layer, where the ruins of a majestic city sleep undisturbed. The buildings spread in every direction and are covered in crystal. It is not uncommon to come across creatures of an irrational danger level here and there even occur geo-thermal explosions that emit poisonous gas and produce the iron rain phenomenon. Avian species in this layer are unaffected by the bird repellent used on the Mail Balloons that delvers send back up to the surface. In a secluded area of the 6th Layer, an entire village inhabited by Narehate called Iruburu was formed.

7th Layer: The Final Maelstrom

 * Depth: 15,500~????? meters.


 * Strains of Ascent: Certain death (alleged).


 * Description: The final known layer of the Abyss. Not much is known about it, but there are many rumors about it transmitted from the Last Dives of generations of White Whistle Delvers, which are only passed down via word of mouth to none but themselves. These include the claim that there exists in it something shaped like a ring, which only a few White Whistle Delvers have been able to see, as well as the rumor that along the path to the bottom of the Abyss live creatures which are shrouded in mystery, called "Gatekeepers". It was at the entrance of this layer that Lyza wrote she apparently first spotted a being similar to Reg. Outside of the reports transmitted by White Whistles, the only other account of this layer were documented in a sealed letter found in the 1st Layer.

The Deepest Point

 * Depth: 20,000+ meters.


 * Strains of Ascent: ???


 * Description: No-one has reached the deepest point, or successfully sent information of it up to Orth, but it is theorized that it is beyond 20,000 meters deep.

Trivia

 * The Abyss is sometimes referred to as the netherworld.
 * The Abyss was inspired by buddhism, as it also has a similar conception of a down-spiralling hell made of different levels in which one is drawn to the bottom.
 * The idea for Made in Abyss was originally planned for Dōjinshi and the Abyss was far smaller initially in concept with a few tens of meters in width.
 * One of the biggest inspirations for the Abyss was the role-playing game, Xenoblade Chronicles.
 * All throughout the Abyss, Delvers report findings of human remnants from civilizations past. All of the skeletons have their hands clasped in prayer, earning them the name, "Praying Skeletons." Little is known about their origin.
 * The island of the Abyss is based off Aogashima with a caldera and color scheme for the sea was based on a Southern island for the anime with the city itself trying to evoke a European feeling to it.
 * Some of the minerals harvested in the Abyss differ depending on the depth of the layer they were mined in. Depth gauges make use of these minerals. Barometers cannot be used in the Abyss because of the force field. Within the device, the minerals change slightly to gas or back to solid. Of course, it can also be used to measure the depth in places other than the Abyss. The gauge used by Riko and Reg, which can measure quite deep, is a rare version of this. It's usually used by Black Whistles.