Nightmare

Biodata

Feature	Value
Name	Nightmare (梦魇)
Alias(es)	Dream Demon
Classification	Anomalous erosive phenomenon that can manifest as individual nightmares, Reality Nightmares, Past Nightmares, or Nightmare Realms 58 213 287
Status	Active
First Appearance	1

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. 92

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. 68 290 313

“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. 92

• Its environment commonly reflects places the Source lived in or frequented. 92
• Its monsters can be shaped by the Source’s fears, obsessions, hatred, attachments, and unfulfilled desires. 92
• 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. 92 99
• Reality Nightmares may be confined to a limited area, such as an industrial park or an airliner and its surrounding airspace. 97 276

Past Nightmare

A Past Nightmare is a Reality Nightmare that has already “died” once, leaving behind a residual nightmare without a conventional active core. 58 287

• 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. 287
• 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. 246 250

• A realm’s number of cores determines much of its potential and upper limit. 280
• Some realms have multiple competing cores, such as the Jester and Owl Judge within the inverted Burns Castle. 246 250
• 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. 213
• A Nightmare Realm can awaken early, detach from its physical site, and relocate. 250

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. 73

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 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. 198
• Nightmare Walkers are generally divided into True Self and Borrowed Power types according to how they wield Erosion. 259

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. 92 213

• Destroying a core can weaken a Nightmare and slow its invasion of reality. 92 99
• 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. 213
• In rule-based Nightmare Realms, multiple cores may compete to consume each other and claim the entire realm’s power. 250
• A core’s associated item may grant authority recognized by the Nightmare, such as Staff Badges in Haunted School. 208

Nightmare Rules

Nightmares impose distorted rules that can govern behavior, identity, movement, and survival. Violating these rules can trigger immediate attacks or death. 73 215

• Rules may be inferred from patterns of victims’ deaths, though this is dangerous and uncertain without prior records. 73
• 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. 215
• Nightmare entities may lose their authority and ability to maintain form when separated from the badges or objects that define their status. 208
• Nightmare power is generally denser at night, when entities become more active and rules more chaotic. 282

Nightmare Demons

Nightmare Demons are rare beings favored by the Nightmare World and described as entities born to devour additional worlds. 286

• They possess exceptional authority in both the Nightmare World and worlds targeted by Nightmares. 286
• A Warlock may become a Nightmare Demon by seizing the sole core of a Nightmare Realm, then growing by devouring further cores and realms. 280
• Nightmare Demons can perceive certain Nightmare-related information unavailable to ordinary humans, such as the text on the Heaven-Questioning Slip. 274
• The Nightmare World’s direct power can strengthen a Nightmare Demon, but uncontrolled intake may damage the user’s sanity. 269

Known Threat Scale

Designation	Documented context
F-rank	A First-Realm martial artist can dominate most threats within an F-rank Nightmare. 100
E-rank	A Second-Realm martial artist can generally ignore most E-rank Nightmare threats. 100
B-rank	Soraka Town is assessed above B-rank because of the Blood Tide. 94
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. 121
S-level danger	Legend Game is described as a super Nightmare with a potential danger level reaching S. 180

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. 243
• The Nightmare Abyss contains regions surrounding many worlds that have already been consumed by Nightmares or reduced to fragments. 313