Sain Underground City

Biodata

Feature	Details
Name	Sain Underground City
Original Name	塞恩地下城
Alias(es)	Sain; Sain Dungeon
Species/Race	Dungeon / Underground City
Dungeon Lord	Gong Qiying, who inherited the identity of the ghoul Godwyn 1
Occupation/Role	Adventure dungeon, resource producer, and Mental Power-gathering ecosystem
Status	Active
First Appearance	Chapter 1

Power Progression

Stage / Realm / Level	Chapter	Notes
Level Three Lord Authority	173	By this point, Sain is recognized as having reached Level Three authority; its trap-, terrain-, and disease-based systems lead another City Lord to reassess it as a serious dungeon.
Level Four Lord Authority	443	Unlocks All-Weather, allowing its opening hours to be freely set, and Temporary Modification, allowing map changes during opening hours at additional Mental Power cost.

Background / History

Sain Underground City was originally a vast but poorly designed dungeon under the ghoul Godwyn. Adventurers could reach its boss room along a single easy route, gather valuable monster materials and minerals with little danger, and leave without casualties. The dungeon therefore failed to generate enough Mental Power to sustain itself. After Gong Qiying transmigrated and became its Dungeon Lord, he judged the old layout to be an unsustainable “treasure vault” and began rebuilding it. 1

Gong reduced the dungeon’s area, reclaimed unused structures for Mental Power, and divided it into upper, middle, and lower layers. The rebuilt route used deceptive side paths, dead ends, elite gatekeepers, darkness, poisonous terrain, and dense monster placement. Its upper layer combined Fort Faroth and Blighttown, culminating in the Twin Gargoyles; later layers included ancient ruins, forests, mines, locked gates, and the Furnace Knight. 1 7

Sain’s redesigned difficulty drew adventurers despite its dangers. Its exploration system gives each party a separate, non-interfering version of the dungeon; defeated monsters and collected rewards reset after the explorers leave and complete a one-day cooldown. 8 The dungeon’s growing notoriety transformed Bed City into a major adventurer and trade center, while Bloodstone mined within Sain became the key ingredient in House of Bede’s Blood Healing Potions. 8

In September 2174 of the New Calendar, Sain went berserk. Count Philip of Bede and Light Eagle Corps mercenaries were killed, and Bed City fell, though no additional casualties were recorded. The incident did not permanently deter exploration: Sain’s unusual items, Campfires, and reputation for not killing adventurers soon made it more prosperous than before. 101

As its Mental Power income grew, Sain expanded beyond its original three-layer structure. Gong divided its content into Souls-like regions centered on traps and attrition, monster-hunting forests, and the accessible Gourmet Area, which combines food with Pokémon-themed creatures and resources. 113 Subsequent additions included Firelink Shrine, Liurnia of the Lakes, underground academy labyrinths, Irithyll of the Boreal Valley, Anor Londo, Caelid, Nokron, Eternal City, and multiple Painted Worlds. 103 254 322 376 722

Sain’s influence spread through Teleportation Gates into the royal capital, the Warrior Nation, Reid, and Scamellon. Its arrival brought adventurers, merchants, resource traffic, and new local industries; it was even considered for recognition as Arnor Kingdom’s “national dungeon.” 467 546 602 758

Layout and Environment

Sain has no fixed, permanent layout. Its terrain, themes, monster placement, and available routes are repeatedly renovated or mutated, with newer areas often connected through Teleportation Gates, traps, hidden routes, or Painted Worlds. 106 515 769

• Original form — A dense, freely explorable ancient architectural complex with abundant minerals, valuable monsters, and easy access to the boss room. 1
• Initial reconstructed form — Three compressed layers: poisonous abandoned villages above, ruins and forests in the middle, and underground mines below. 1
• Souls-like regions — Fort Faroth, Blighttown, mines, catacombs, Irithyll, Anor Londo, and related areas emphasize traps, hostile monsters, obscure routes, and elite encounters. 7 113 265 321
• Forest Area — Focused on one-on-one battles against magical beasts; later equipped with a forge that lets adventurers craft selected equipment from monster-hunting materials. 113 188
• Gourmet Area — A comparatively safe food and resource zone open to ordinary people as well as adventurers. Its ingredients can provide restorative effects. 113 377
• Painted Worlds — Specialized role-playing or exploration environments that can occupy entrants for extended periods. 764 790

Abilities & Systems

Mental Power Ecosystem

Sain is sustained by Mental Power generated through adventurers’ emotions and experiences. Its design prioritizes a cycle of challenge, reward, failure, curiosity, and return visits. 1 613

• Mental Power pays for the dungeon’s daily operation and the summoning of monsters and structures. 1 7
• Dangerous traps, unfamiliar diseases, oppressive terrain, and difficult encounters are major sources of adventurer emotion and therefore Mental Power. 173
• Sain can adjust Mental Power extraction standards in response to conditions within specific areas. 376
• Its territorial influence appears on the World-Dyeing Map as green coloration; surrounding regions can become fully “dyed” by Sain’s influence. 176 602

Instanced Exploration

Each explorer or recognized team enters an individual version of Sain rather than competing directly for the same monsters and rewards. 8

• The portal identifies teammates and normally prevents parties from entering one another’s instance by mistake. 8
• Looted rewards and defeated monsters recover after explorers leave and a one-day cooldown passes. 8
• Certain regions use special reset rules; in Sellia Crystal Tunnel, monster positions and states reset when a party is wiped out, while the exit route changes after every wipe. 515

Adaptive Dungeon Behavior

Sain can react automatically to the behavior patterns of its explorers according to standards set by Gong Qiying. 637

• Cautious, methodical parties may encounter fewer traps but more direct monster confrontations. 637
• Monster-group distribution can be adjusted to reflect adventurers’ usual exploration habits. 637
• Adventurers who visibly value Sain may receive subtle favorable adjustments, such as a slightly improved chance of finding higher-grade light-point drops. 755

Dungeon Lord Authorities

Gong Qiying manages Sain through the Dungeon Lord’s model, allowing him to inspect, redesign, and populate its maps. 1

• He can build and dismantle terrain, structures, traps, routes, monster placements, and reward locations while the dungeon is closed. 1 7
• Level Four authority permits temporary modifications while Sain is open, though these consume additional Mental Power. 443
• Level Four authority also permits unrestricted control over opening hours, including continuous operation or complete closure. 443

Campfires, Sites of Grace, and Progression

Sain provides Campfires and Sites of Grace that facilitate adventurer advancement and preserve fragments of the dungeon’s embedded stories. 106 789

• Campfire imagery encourages explorers to investigate Sain’s lore, historical figures, and unfamiliar place names. 106
• Campfires and Sites of Grace can steadily improve an entrant’s physical capabilities toward the level of an experienced warrior. 789
• Battle Skills, magic, equipment, soul blocks, and other dungeon rewards supplement this gradual growth. 7 789
• Sain appears to regulate advancement so that most entrants improve incrementally rather than through uncontrolled leaps in power. 789

Resources and Rewards

• Bloodstone — Red ore mined in Sain and used as the main ingredient of Blood Healing Potions. 8
• Battle Skill weapons — Sain can produce weapons with innate Battle Skills, such as the Greatsword discovered in Blighttown. 7 8
• Hound’s Step claws — Reward granted to Sithran after she navigated a trap successfully. 21
• Summoning Finger Medicine — Item awarded alongside the Hound’s Step claws. 21
• Monster-derived food — Gourmet Area food can heal injuries and reduce demand for conventional healing potions. 377
• Moss Balls — Introduced through Fort Faroth; useful enough to disrupt antidote and coagulation-potion sales. 377
• Torrent and Lone Wolf Ashes — Free rewards that caused widespread excitement in Black Stone City. 548
• Crafting materials — Forest Area monster hunts can yield materials for use at its forge. 188
• Eternal King’s Mimic Tear — A Nokron-related item capable of transforming into the Elden Lord and other phantoms. 722

Relationships

• Gong Qiying / Godwyn — Dungeon Lord and primary designer. Gong inherited Godwyn’s position, rebuilt Sain, and continually expands its maps and systems. 1 722
• Bed City — Sain’s original neighboring city and early economic partner; adventurer traffic, Bloodstone mining, and trade reshaped the city’s economy. 8 101
• Adventurer’s Guild — Established a public notice board and reward system for intelligence discovered inside Sain. 106
• Val Dungeon — Another dungeon controlled by Gong Qiying; adventurer traffic to either dungeon ultimately benefits the same City Lord. 134
• Red Fang Dungeon — Powerful allied City Lord that invited Sain to a punitive expedition and collaborated with it on cross-dungeon events. 252 347 348
• Cangyin Underground City — Cooperative dungeon managed by Hainis; the two exchange maps, mutant plants, and design knowledge. 616 645
• Blazing Flame Dungeon — Rival dungeon led by Flamefire; Sain accepted its dungeon battle challenge and later emerged victorious. 698 700 758
• Holy Light Dungeon — Hostile neighboring dungeon whose City Lord repeatedly sends requests, gifts, and deathmatch invitations to Sain. 758 790
• Starfire Church — Uses Sain’s areas, Covenants, maps, and resources to support exploration and its war effort in Scamellon. 753 775 776

Story Role / Major Arcs

Rebuilding the Easy Dungeon

Gong Qiying inherits Sain when it is a failing, overly generous dungeon and rebuilds it around dangerous progression, traps, strong rewards, and Mental Power generation. 1 7

Rise of Bed City

Sain’s anomaly and expanding content attract adventurers, miners, black-market dealers, merchants, and researchers. Bed City becomes increasingly dependent on the dungeon’s traffic, resources, and discoveries. 8 41 114

Berserk Incident

Sain goes berserk in September 2174, killing Count Philip and Light Eagle Corps mercenaries before becoming prosperous again due to its distinctive items and reputation. 101

Age of Great Mutation

Sain’s repeated renovations and success inspire other dungeons to begin their own mutations. Its combination of traps, lore, food, monsters, equipment, and role-playing content becomes widely imitated but difficult to replicate. 188 262 347

Multi-Nation Expansion

Through Teleportation Gates and branch-city development, Sain establishes a presence in the royal capital, Reid, the Warrior Nation, and Scamellon, turning it into a major strategic and economic force. 467 546 602 757

Dungeon Rivalries

Sain’s territorial growth and popularity provoke resentment from neighboring dungeons. It enters a dungeon battle with Blazing Flame Dungeon, while Holy Light Dungeon continues to seek confrontation. 681 698 700 758

Ongoing Exploration Crisis

New regions such as Nokron continue to open, but the mysterious disappearance of Skyline Strategy Group leaders—including Luluwo—inside Sain becomes a major unresolved incident. 706 790

Trivia

• Sain’s early rebuild was explicitly inspired by Gong Qiying’s familiarity with the Dark Souls series. 1
• Its initial redesigned version was estimated to have a 50% fatality rate. 7
• Sain’s monsters are noted for being malicious toward intruders and particularly inclined to embarrass people who try to show off. 203
• Its content is not limited to combat: it supports food markets, crafting, magical study, role-playing, lore research, tourism, resource collection, and adventurer training. 41 188 764
• The dungeon has repeatedly been mistaken for a fully historical ancient city because some of its environments feel like lived-in remnants of another era. 261