The Curse of the Abyss

"Nanachi"

- That's the true nature of the Curse of the Abyss. There's nowhere to escape from it.

The Curse of the Abyss (アビスのい) or Strains of Ascension refer to a series of afflictions experienced by Delvers when ascending within The Abyss. Conditions range from mild dizziness up to severe body deformation and death. Barring extreme circumstances, the Curse is unavoidable. Among all of its famed perils, the Curse represents the Abyss's greatest hazard.

Description
The effects of the Curse manifest after an individual's vital organs ascend more than 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.

Common Effects
These effects are experienced near-universally. While it is possible for Delvers to acclimate to some of the effects or navigate areas with less severe consequences, they cannot be avoided altogether.

1st Layer

 * Mild dizziness
 * Nausea

Nat was shown to have thrown up from nausea, when returning to Orth, and also acknowledged a pain in his head.

2nd Layer

 * Intense nausea
 * Headaches
 * Numbness of the extremities

When Riko had been caught by a Corpse-Weeper in the Forest of Temptation, she threw up and passed out as a result of suffering the strains of the 2nd Layer.

3rd Layer

 * All effects of the previous layers
 * Vertigo
 * Visual and auditory hallucinations
 * Problems with sense of balance

When ascending in the Great Fault, Riko was shown to have suffered headaches, severe nausea, dizziness, problems with her sense of balance, and thrown up. She also experienced visual and auditory hallucinations of Marulk, Ozen, Shiggy, Nat, Kiyui, Hablog, and a particularly vivid hallucination about returning to Orth with her mother, Lyza.

4th Layer

 * Intense pain throughout the body
 * Bleeding from every orifice

After Reg had gathered Riko for a retreat from the Orb Piercer, Riko was struck with elements of the Curse from both the 3rd and 4th Layers. She was shown to be in a delirious state, in intense pain, hallucinating, and also bleeding from her every orifice.

5th Layer

 * Loss of all senses
 * Confusion
 * Self-harm

Nanachi was shown to have left a trail of excreted blood, while leaving the Ido Front with Mitty. Nanachi later acknowledges that they had acclimated to the strains of the 5th Layer and are able to maintain consciousness while suffering the strains of ascension.

Prushka was shown to have suffered major mental, physical, and psychological damage as a result of suffering the strains of the 5th Layer. Many of her injuries have since healed, but as she was not known to recall her previous life, it's unclear how much damage to her remained permanent. Using the scent of Meinya, she was able to learn to navigate the Curse.

While under the sway of the 5th Layer's curse, Riko suffered a total loss of her senses. Unable to hear her own voice, total loss of spatial awareness, and unable to recognize her own physical being. This resulted in a number of minor injuries to her teeth, cheek, and her right hand. During the episode, she had no sense of pain, only experiencing it after having recovered.

6th Layer

 * Loss of humanity
 * Death (only in some cases)

Former child subjects of Bondrewd's experiments were shown to have been inhabiting the Miniature Garden Of Dawn. Their deformed bodies are the result of having suffered the curse of the 6th Layer.

Vueko was shown to have suffered from the Curse of the 6th Layer, while attempting to ascend in The Village of Iruburu, after the barrier protecting the village from the Force Field had been breached. She acknowledged the great pain of the transformation and was shown to have lost her ability to speak. Although she only partially suffered from loss of humanity, the effects still proved fatal.

7th Layer

 * Certain death (alleged)

The prevailing dogma among Delvers says that the Curse of the 7th Layer is “certain death”. However, only one recorded instance of the 7th Layer's curse has ever reached the City of Orth. The document containing this scarce knowledge was lost before it could be fully investigated. And thus the true nature of the 7th Layer's Curse remains unknown.

Rare Effects
Under certain circumstances, The Abyss may impart unusual, lasting physical changes on the recipients of its curses. While they are not clearly understood, they are capable of being replicated.

The Blessing
The blessing is one of the most enigmatic phenomena of The Abyss and, thus far, has only been achieved through the extreme undertaking of suffering the 6th Layer's Curse.

For the blessing to be successful, one participant must bear the strain of the 6th Layer for both themselves and another individual which they hold dear and love. It is only through this great sacrifice that both individuals undergo this unique transformation. The individual shielding the Curse will suffer the Curse's regular effects (loss of humanity and/or death), while the individual being shielded (the blessed) loses their human form but retains their human faculties.

The full consequences of the blessing ritual have not yet been fully explored, but in the case of Nanachi and Mitty, the pair were shown to have picked up peculiar attributes: Nanachi gaining a pleasant smell and an ability to see the Force Field and Mitty gaining immortality.

Bondrewd, having also achieved the blessing for himself, gained a body of great strength and the ability to also see the Force Field. However, because of the short-lived nature of his form and Prushka's humanity having effectively already been stripped away, it is unknown what other changes the two may have otherwise undergone.

Netherworld Locks
The Abyssal hair twirls are a phenomenon that seemingly only affect delvers that experience the Curse at deeper layers of The Abyss. The affected delver's hair gains noticeable curls of varying intensity. The exact reasons for its effect are unknown.

Prushka gained her curly hair after experiencing the Curse of the 5th Layer for the second time and expressed confusion that Riko hadn't developed similar hair after having also suffered the 5th Layer Curse.

Tepaste was acknowledged to have the Abyssal twirls by Yelme, at the Plummet Pub. The exact circumstances of her twirls are currently unknown.

Persistent Headaches
Riko, while having otherwise healthy eyesight, requires lenses constructed from crystals found in The Abyss. Without these special lenses, she is prone to headaches. This particular ailment is assumed to have been brought upon by suffering the Curse at such an early age and is something that Lyza had lamented she was unable to spare her daughter from.

Trivia

 * There are areas where the Force Field that causes the Curse is weaker and less severe. In certain places, such as Nanachi's Hideout and The Village of Iruburu, the Curse is not present.