Abyss

Biodata

Feature	Value
Name	Abyss (深渊)
Type	Interdimensional realm / anomalous phenomenon
Status	Its surface entrance was sealed by Abyss Iron after 80 years of influence on humanity; the seal continued to thicken afterward. 1192 1193
First Appearance	Chapter 5: Abyss First Layer and Relic Hunters 5

Known Layers

Layer	Known region / condition	Access and defining characteristics
First Layer	Forest of Aberrations	The largest known layer, rich in strange creatures and Relics; it was the primary source of incursions into the human world and remained a major research area. 5
Second Layer	Disordered Sand Dune	Reached through the Reversal Mountain Range, where gravity progressively weakens and reverses beyond the peak. It is a major Relic-producing region. 66 1112
Third Layer	Creation God Sea	Intertwined with the Second Layer like sea and beach; travelers descend by riding sand waves toward the sea. 208
Fourth Layer	Sky Island Fault / Sky Sea Fault Line	A chaotic region of floating sky islands, unstable clouds, and turbulent currents affected by the Third Layer’s seawater, the Abyss Hole’s filtering, and local forces. 460 1136
Fifth Layer	Eternal Night	A perpetually dark region where light attracts creatures; its landscapes include anomalous areas such as Bent Regions and Ashfall Zones. 687 819
Sixth Layer	—	Reached after death through an entrance hidden in a peaceful grassland; it contains ruins of human civilizations from parallel worlds. 969 1151
Abyss Bottom	Text Canopy	A region whose ground is densely inscribed with human text; its writing appears capable of describing—and potentially altering—worlds. 1156 1165

History

The Abyss entered human awareness when a vast void appeared in what became Dawn City during the Great Cataclysm. Abyss creatures and Relics emerged from it and invaded the world before humanity drove them back into the Abyss. Exploration then became an organized and highly dangerous pursuit, with explorers known as Hunters. 5

Humanity gradually established Monitoring Stations, supply networks, research programs, routes between layers, and settlements within the Abyss. These systems enabled further exploration but also accelerated the integration of Abyss creatures, Relics, and technology into human society. 5 66 867

Eighty years after the Abyss’s arrival, square-structured Abyss Iron spread across the entrance and sealed it without attacking nearby human facilities. The closure cut off the emergence of new Relics and permanently separated some Abyss Dwellers from the surface. 1192 1193

Nature

The Abyss is understood through competing and incomplete models rather than a single confirmed explanation. Researchers and explorers have characterized it as a devouring entity, a breeding ground for chaos, an ecosystem, an immune system, a selection tool, or a weapon; no interpretation is presented as complete. 1133 1241

One influential theory holds that the Abyss appears across many parallel human worlds, connecting them and consuming those unable to resist. The human ruins found in the Sixth Layer are believed to be remnants of such worlds, preserved in the state of their destruction. 969

Rather than simply destroying humanity, the Abyss erodes the meaning of human existence. Human language, history, religion, geography, and social practices may persist after humanity disappears, but become detached from their origins and absorbed into other civilizations. 1055

Rules and Mechanisms

Cost

Power in the Abyss is inseparable from cost. Relics grant abilities beyond normal human technology, but users must pay a corresponding price; deeper-layer Relics generally possess both greater effects and harsher costs. 5

• Relics may impose a one-time or recurring price. 5 53
• Relic misuse can pollute individuals and destabilize civilization by creating extreme power inequality. 970
• Human authorities treat cost as the central warning in Relic education and regulation. 867

Synchronization

Travel from the Third Layer to the Fourth Layer requires Synchronization, which accelerates a traveler to the Fourth Layer’s temporal rate and renders their body sufficiently “chaotic” to fit its space. 457

• Synchronization binds external travelers to the Abyss’s time flow. 1151
• Time passes drastically faster on the surface after reaching the Fourth Layer: one day in the Abyss may correspond to years above. 1151
• Many Third-to-Fourth-Layer passages were created by humans. 457

Anchoring and the Abyss Hole

The Abyss Hole is the passage from the Fourth Layer to the Fifth Layer. It functions as a funnel that filters what the Abyss considers relevant, excluding unanchored external objects. 655 1137

• Humans require a more demanding Anchoring process than other external objects: they must participate in Abyss events and become part of its development. 1137
• Successful Anchoring grants qualification to enter the real Abyss Hole. 683 684
• The Hole’s filtering process can discard possessions, separate travelers, and force them into different landing areas. 655 687
• The Abyss Hole developed consciousness while resisting chaos and entropy; it became a lifeform despite originating as a tool. 821

Projection

Below the Abyss Hole, the Abyss uses projection to connect meaningful and meaningless things. It projects distorted physical rules as connective “textures,” similar to rods linking figures in a shadow play. 819

• Projection can stretch, distort, cut, and combine phenomena. 819
• Imperfect projections create anomalous regions and physical-rule errors. 819
• Ashfall Zones result from repeatedly projected Brownian motion, which superimposes random forces until matter is shattered into airborne dust. 819

Ecosystem

Life in the Abyss adapts to highly unstable local rules rather than ordinary environments. Even at the boundary between the First and Second Layers, seeds drift through near-zero gravity and either establish themselves in new terrain or become nourishment for other organisms. 1112

The Abyss’s inhabitants are not uniformly aligned with it. Some Abyss races resent the world that created them because it continually makes their environment more complex, unstable, and cruel. 1136

Powerful Abyss beings may eventually become “Heavenly Dao-ized”: rather than dying, they lose their individuality and become persistent rules or regional phenomena within the Abyss. 1129

Relationship with Humanity

• Hunters — Humans who enter the Abyss in pursuit of Relics, knowledge, profit, personal desires, or humanity’s future; they are publicly framed as heroes but regarded by authorities as possible calamities. 5 867
• Monitoring Stations — Human outposts that monitor anomalies, conduct research, supply Hunters, release tasks, and coordinate Abyss operations. 5
• Abyss Superhumans — Relic-altered humans whom authorities consider too dangerous to return freely to society; many were confined in Dream City or sent to permanent “Prison Cities” below the Abyss Hole. 867 895
• Abyss Dwellers — Humans who made homes within self-sufficient Abyss cities and, after the entrance closed, became permanently separated from the surface. 1193
• Abyss Heart Technology — A major company that integrated Relics and Abyss creatures into civilian technology, contributing to humanity’s technological boom and dependence on the Abyss. 867 1220

Sealing by Abyss Iron

Abyss Iron is an anomalous metal composed of square atoms and electrons that cannot be interpreted through normal cognition. It spread over the surface entrance, deliberately avoiding human research facilities and sealing the Abyss without outward expansion or conflict. 1192

• Tests suggested that Abyss Iron can make choices according to human concepts of good and evil, tending toward benevolence. 1194
• In one experiment, an Abyss Iron sample refused to transmit a signal that would have activated a device killing a laboratory rat. 1194
• Researchers proposed that it may have originated from a human Forerunner who entered the Abyss, gained the ability to create Abyss Iron, and was assimilated while sealing the entrance. 1198
• A photograph taken ten years after the sealing showed a strange Cube standing on the Abyss Iron layer. 1194