Nightmare

Biodata

Feature	Value
Name	Nightmare (梦魇)
Alias(es)	Dream Demon
Classification	An anomalous erosive phenomenon that can manifest as individual nightmares, Reality Nightmares, Past Nightmares, or Nightmare Realms; at its highest level, Nightmare is the supreme existence and Path from which Nightmare-related power is born and by which it is governed. 58 214 288 434
Status	Active
First Appearance	1

Power Progression

Stage	Documented development
Modern escalation	Nightmare infections increased steadily after the turn of the millennium, with suspected Nightmare Syndrome deaths reaching more than three hundred in one city during a single year. 11
Abyssal disturbance	The creation of Zhou Kai's Nine-Core Demon Realm drew immense power from the Bottom of the Dream Demon and provoked Nightmare's fury; a gigantic eye opened beneath the Abyss. 373
Eye-opening event	During the conflict in the Nightmare Abyss, the Dream Demon itself opened an eye, creating a major disturbance and an unprecedented variable in the abyss’s previously fixed certainty. The event was considered a possible sign of a new True Lord’s emergence. 375
New Nightmare World threat	Grey World evolved from a Nine-Core Demon Realm into an embryonic Nightmare World whose Grey World Law can absorb Dream Demon Rules and use their fragments to create new Dream Demons. 376
Seventh-Realm response	Once Grey World became a New Nightmare World Prototype and attained the Seventh Realm on the Nightmare Path, Nightmare’s concealment-resistant attention was drawn to it. Nightmare regards such a prototype as a threat that must be eliminated. 434
Possible full awakening	Mingzhen warned that “His” awakening was approaching, which Zhou Kai suspected referred to Nightmare. White King further stated that Nightmare’s impending awakening could destroy the Nightmare Abyss and all worlds within it. 431 436

Nature

Nightmares are an “irresistible force” capable of transcending death, eroding living beings, and dragging parts of reality into the Nightmare World. Their arrival does not follow a known emotional, geographic, or social pattern; attempts to prevent them by reducing public stress through entertainment proved ineffective. 93

Nightmares have reportedly existed for hundreds of years, but infections have increased steadily since the turn of the millennium. The Bureau of Abnormal Affairs recorded more than three hundred suspected Nightmare Syndrome deaths in one city during a single year. 11

Beyond individual nightmare scenarios lies the Nightmare World: a vast realm of eternal night extending far beyond Soraka Town. It contains surviving human settlements, Warlock city-states, martial-artist sects, adventurer towns, Black Walls, and drifting fragment worlds. 68 291 314

The Nightmare Abyss encompasses worlds at different stages of consumption. Regions below Nether Truth outposts contain exhausted worlds nearing their fall to the Bottom of the Dream Demon, world fragments, and drifting Nightmare Realms; regions above them contain worlds that have only recently been touched by Nightmare and remain under Erosion. 327

The emergence of Zoomorphic martial artists within a world is reportedly an indication that the world has reached its final stage before destruction. 326

During the conflict in the Nightmare Abyss, the Dream Demon itself opened an eye, causing a major disturbance and introducing a new variable into the abyss’s previously fixed certainty; this event was considered a possible sign of a new True Lord’s emergence. 375

At the highest level, Nightmare is both the name of the supreme Nightmare World and the Nightmare Path itself. Nightmare gathers negative elements—including destruction, pain, and despair—and all Nightmare-related power is described as being born from and governed by it. 434

A New Nightmare World Prototype is fundamentally hostile to Nightmare’s continued existence. Such a world would need to parasitize the old Nightmare World and endlessly draw upon its power to nourish its growth; if that process continued, the new world could gain life while the old Nightmare World declined. 434

Mingzhen’s messages and White King’s testimony indicate that Nightmare may be approaching a fuller awakening. If this occurs, it may destroy the Nightmare Abyss and the worlds contained within it. 431 436

“In the Nightmare, despair ferments.” 7

Forms and Classifications

Reality Nightmare

A Reality Nightmare is linked to an infected person in the real world, referred to as a Source or Nightmare Spirit. The infected person is believed to be infected first, subsequently drawing the Nightmare into reality. 93

• Its environment commonly reflects places the Source lived in or frequented. 93
• Its monsters can be shaped by the Source’s fears, obsessions, hatred, attachments, and unfulfilled desires. 93
• Killing the Source before full descent can interrupt the Nightmare’s arrival; after descent, killing the core can only weaken the Nightmare and delay its consumption of reality. 93 100
• Reality Nightmares may be confined to a limited area, such as an industrial park or an airliner and its surrounding airspace. 98 277
• Reality Nightmares exceeding A-rank exist; the Great Dream Treasure Vase of the Wind-Fire Way was stated to contain the full power of one such Nightmare. 342

Past Nightmare

A Past Nightmare is a Reality Nightmare that has already “died” once, leaving behind a residual nightmare without a conventional active core. 58 288

• A Past Nightmare can infect only one person at a time. 58
• It lacks a Reality Anchor and cannot merge with reality a second time. 58
• The Walker entering it functions as its effective core, but lacks the authority normally possessed by a Nightmare Realm Core. 288
• Failure to handle one may still produce secondary disasters such as Mirage Monsters. 58

Nightmare Realm

Nightmare Realms are more developed nightmare spaces with cores, entities, environmental rules, and the potential to expand or move through reality. 247 251

• A realm’s number of cores determines much of its potential and upper limit. 281
• Some realms have multiple competing cores, such as the Jester and Owl Judge within the inverted Burns Castle. 247 251
• Composite Dream Demons, also called Desperate Realms, consist of multiple connected nightmare zones; destroying one zone’s core can collapse that section without ending the larger realm. 214
• A Nightmare Realm can awaken early, detach from its physical site, and relocate. 251
• Human-derived Realm Cores may retain memories from before death, while their malicious thoughts are magnified without limit. 275
• The six-core Subway Nightmare Realm possesses the greatest growth potential Zhou Kai had encountered at the time of its revival. 275
• Nightmare Realms can serve as energy nodes for Great Dream Boats, whose inter-network-path travel requires multiple realms to form a closed energy circuit. 328

New Nightmare World Prototype

A New Nightmare World Prototype is an embryonic independent Nightmare World formed through the evolution of a sufficiently powerful Demon Realm. Grey World arose from Zhou Kai’s Nine-Core Demon Realm and is considered an unprecedented example. 376 434

• Grey World’s nine former rules merged into the Grey World Law, which can absorb additional Dream Demon Rules and convert their fragments into new Dream Demons. 376
• The prototype developed into a massive nightmare continent capable of housing and developing its own inhabitants, systems, and subordinate Dream Demons. 376
• Grey World’s growth could theoretically be accelerated through the accumulation of Warlock and Nightmare Rule fragments. 376 434
• Nightmare itself considers a New Nightmare World Prototype intolerable because it could parasitize the old Nightmare World and compete for its power. 434
• Grey World’s emergence as a Seventh-Realm Nightmare-Path existence caused its concealment to fail and attracted the attention of powerful entities throughout the Abyss. 434

Mirage

A Mirage is a Nightmare Monster associated with the deaths of Nightmare Walkers. Its exact origin remains uncertain, though one major theory identifies it as the remaining husk of a Walker who died in a nightmare. 35 37

• Nightmare Syndrome patients usually die physically from organ failure, cardiac arrest, or similar causes. 35
• When a Nightmare Walker dies, their body may disappear from reality entirely. 35
• Wild Walkers are especially dangerous to investigate after death because their killing rules and Nightmare history are unknown. 74

Nightmare Syndrome and Walkers

Nightmare Syndrome begins with recurring deaths in the same dream. Each death weakens the victim’s physical body in reality, and untreated patients may die within five to nine days from organ failure, cardiac arrest, or brain death. 9

A person may become a Nightmare Walker by obtaining proof of identity within the nightmare—such as a badge, key, permit, or armband—and activating a special structure that establishes a foothold. 11

• Known special structures include Bonfires, Fireplaces, Incense Burners, Nurseries, and Shrines. 2 11
• A special structure can only be used by the infected subject acknowledged by that specific Nightmare; merely obtaining its associated item is insufficient for an outsider to become its Walker. 139
• A Walker may enter voluntarily at midnight or be forcibly pulled into the Nightmare after seven days. 3
• A voluntary entrant can leave a Nightmare at any time; a passive entrant requires a tombstone or sufficient flame to remain alive and leave. 7
• Remaining in an initial Nightmare for longer causes the Dream Demon World’s hostility toward its Walker to escalate. 199
• Time in the opposite world is effectively frozen for a Dream Demon Walker while they are present in another world. 201
• Anchor Points allow Dream Demon Walkers to pass through Rift Land and travel between connected Dream Demons across immense distances. 205
• Nightmare Walkers are generally divided into True Self and Borrowed Power types according to how they wield Erosion. 260

Cores, Entities, and Rules

Nightmare Cores

A Nightmare Core is a conduit through which Nightmare power erodes its surroundings. It may be a Source, a monster, an object, or a divided set of sub-spirits. 93 214

• Destroying a core can weaken a Nightmare and slow its invasion of reality. 93 100
• Some entities are sustained by hidden objects rather than their apparent authority; the giant face in Haunted School persisted through a mask after its Staff Badge was removed. 214
• In rule-based Nightmare Realms, multiple cores may compete to consume each other and claim the entire realm’s power. 251
• A core’s associated item may grant authority recognized by the Nightmare, such as Staff Badges in Haunted School. 209
• The loss of an authority item can deprive an entity of its Nightmare-recognized status, preventing it from maintaining its form or exercising its prior authority. 209
• A Warlock who seizes a realm’s sole core can become a Nightmare Demon; subsequent growth involves devouring further cores, realms, and their associated rules. 281

Nightmare Rules

Nightmares impose distorted rules that can govern behavior, identity, movement, and survival. Violating these rules can trigger immediate attacks or death. 74 216

• Rules may be inferred from patterns of victims’ deaths, though this is dangerous and uncertain without prior records. 74
• Authority items can alter how a Nightmare recognizes an individual; Zhou Kai’s Pseudo-Human body and Staff Badge allowed him to bypass many Haunted School rules. 216
• Nightmare entities may lose their authority and ability to maintain form when separated from the badges or objects that define their status. 209
• Nightmare power is generally denser at night, when entities become more active and rules more chaotic. 283
• High-level Nightmare items continually leak Erosion, making storage equipment capable of containing them exceptionally rare. 252
• Nightmare Marks may establish a rule-based pursuit relationship between a marked target and Nightmare entities. A previously marked Dream Demon Giant continued hunting Zhou Kai and used the mark’s associated rules to locate him again after its earlier defeat. 399
• Nightmare influence can extend to virtual existences through Nightmare Viruses, which may generate Dream Demons and erase data-based lifeforms entirely. 379

Nightmare Demons

Nightmare Demons are rare beings favored by the Nightmare World and described as entities born to devour additional worlds. 287

• They possess exceptional authority in both the Nightmare World and worlds targeted by Nightmares. 287
• A Warlock may become a Nightmare Demon by seizing the sole core of a Nightmare Realm, then growing by devouring further cores and realms. 281
• Nightmare Demons can perceive certain Nightmare-related information unavailable to ordinary humans, such as the text on the Heaven-Questioning Slip. 275
• The Nightmare World’s direct power can strengthen a Nightmare Demon, but uncontrolled intake may damage the user’s sanity. 270
• Ordinary Nightmare Demons commonly require at least two cooperating Realm holders to operate a Great Dream Boat through the gaps between network paths. 328
• Nightmare Demons and Warlocks regard worlds under Nightmare’s influence as sources of Nightmare Realms, resources, and potential prey. 327 328
• A Nightmare Demon’s initial Realm Core count substantially affects its later potential; high-level figures may command several rules that have each undergone qualitative transformation. 327

Nightmare Seeds

Nightmare Seeds are means by which Warlocks spread their power and cultivate successors in other worlds. 328

• Warlocks lack ordinary reproductive ability and instead use Nightmare Seeds to establish disciples and propagate their teachings. 328
• A recipient whose seed sprouts enters the first Warlock realm, Hatchling, and gains the ability to wield the seed’s Nightmare power. 328
• From Hatchling through Crawl and Cocoon-Breaking, a Warlock adapts to the seed’s associated power; a Foundation Establishment Nightmare Demon generally seizes and refines a Nightmare Realm derived from that same power. 328
• Seeds can preserve memories and strands of Warlock power, allowing their recipients to gain protection or advancement while acting within a target world. 328
• Warlocks may plant seeds in foreign worlds to establish remote agents, cultivate new Nightmare Demons, and ultimately consume the resulting entities or worlds. 328
• In worlds with accelerated time flow, Nightmare Seeds can spend a century cultivating internally while only days or weeks pass in the Nightmare Abyss. 327

Known Threat Scale

Designation	Documented context
F-rank	A First-Realm martial artist can dominate most threats within an F-rank Nightmare. 101
E-rank	A Second-Realm martial artist can generally ignore most E-rank Nightmare threats. 101
B-rank	Soraka Town is assessed above B-rank because of the Blood Tide. 95
A-rank	A flame-wreathed entity capable of burning a target from one hundred meters away was speculated to belong to an extremely high-ranked Nightmare. 122
Above A-rank	The Great Dream Treasure Vase of the Wind-Fire Way was said to contain the complete power of a Reality Nightmare above A-rank. 342
S-level danger	Legend Game is described as a super Nightmare with a potential danger level reaching S. 181
Fifth Realm	The Dream Demon Giant, the Progenitor of the Man in the Mist, and thousands of Men in the Mist were identified as Fifth-Realm or Lower Fifth-Realm Nightmare entities. 399
Earth Calamity	Ghost Lake Earth-Calamity’s mere presence in reality caused storms, corpse rain, floods, tsunamis, and contaminated rainfall that killed hundreds of thousands. 324
Seventh Realm	Grey World’s ascension to the Seventh Realm on the Nightmare Path established it as a New Nightmare World Prototype capable of challenging Nightmare’s monopoly over Nightmare Power. 434

Trivia

• Early official containment methods for identified Reality Nightmare infections included secret execution, reducing the proportion of Reality Nightmares while raising severe ethical concerns. 58
• Nightmare energy is more concentrated in Gotham City than in Xishan City, where it is described as more than ten times denser. 244
• The Nightmare Abyss contains regions surrounding many worlds that have already been consumed by Nightmares or reduced to fragments. 314
• The failure of a Walker’s special structure after their death remains a subject of concern among Nightmare responders, since permanently retained structures could otherwise provide lasting shelters within low-level Nightmares. 122
• The expression “only nightmares can fight nightmares” is used by multiple factions to justify employing Nightmare power against Nightmare threats, despite the corruption risks involved. 59 317
• Nightmare influence is not limited to biological life: virtual inhabitants of the Rune Civilization’s mainframe can be infected, erased, or transformed through Nightmare Viruses. 379