Underground Cave

Biodata

Background / History

In December 1920, a catastrophic earthquake—later identified as the opening of a new Underground Cave entrance—caused hundreds of thousands of deaths in Huaxia. The public revelation of martial artists and the establishment of the Capital Martial Arts Society followed in 1921. 14

Underground Caves are complete worlds beneath the earth, with their own civilizations but without modern civilization. Their entrances are not fixed and may appear anywhere; earthquakes are a major sign of cave activity. Nearly twenty entrances had been discovered in Huaxia at the time of Wu Kuishan's explanation. 14

The cave peoples repeatedly attempt to break through the entrances into the surface world, while humans can only enter through the established cave passages. Their assaults create surface tremors; stronger tremors indicate a greater risk of a breakthrough, prompting humanity to deploy martial artists to inflict enough casualties to force a retreat. 14 15

Access and Defense

• Martial University students may voluntarily enter after reaching Third Rank, though most wait until Third-Rank High Stage because their survival chances are substantially better. 15
• In wider society, knowledge of the Underground Cave is restricted until Third-Rank High Stage; Fourth-Rank martial artists begin facing compulsory conscription. 9
• Technological products are prohibited from being brought into the Abyss. 34
• Entrance facilities are guarded by military forces, screening checkpoints, a mission hall, and an A-Grade Alloy defensive door built around the original Energy Passage. 34
• Materials retrieved from the caves can be exchanged through the Military Department or designated purchasing locations. 34
• Martial artists who regularly fight below are recognized as Abyss Warriors, distinct from surface martial artists. 34

Nature and Inhabitants

• The Underground Cave world contains a far greater number of martial artists than the surface world. 14
• Its inhabitants include Underground Cave Humans, Abyss Warriors, Demon Beasts, Demon Plants, and True Kings. 49 101 215
• Underground Cave combat and cultivation methods principally use energy, rather than the Blood Qi used by human martial artists; differences in bodily structure also affect cultivation research. 88
• Cave warriors fight in organized groups and employ ambushes. Even a powerful intruder may be hunted by teams of Fifth- or Sixth-Rank warriors. 26 37
• Underground Cave warriors commonly destroy their own Energy Stones and hearts before death to deny resources to human enemies. 38

Resources and Economy

• The Underground Cave is considerably richer in cultivation resources than the surface world. 15
• A fingernail-sized piece of Energy Ore can be exchanged for a High-Rank pill; ore can be found in outer regions, though larger deposits lie deeper within the caves. 15
• Cave forces and creatures use Energy Ore, while weapons, pills, medicinal herbs, spirit fruits, and Energy Stones are also recovered through exploration and warfare. 15 34
• Mineral veins are central strategic assets. In Demonwood City, veins of roughly 40%–70% purity were common, while deposits exceeding 80% purity were rare. 101
• Royal-city mineral veins may be guarded by Demon Plant roots capable of exerting Fourth- or Fifth-Rank force individually. 101
• Resource scarcity drives the conflict: Su Yi characterizes humanity as willing to fight desperately because it is comparatively poor, while resource-rich cave cities are less willing to risk all-out destruction. 146

Known Regions and Settlements

Hope City

Hope City is one of humanity's major strongholds in the Demon Capital Underground Cave, but it is not completely safe. It serves as a defended base, passage hub, mission center, and staging point for surface martial artists entering the Abyss. 15 34

Heaven's Gate City

Heaven's Gate City is Hope City's principal enemy in the Demon Capital Underground Cave. Su Yi's parents died while undertaking a mission to clear the Meat Grinder after their team encountered one of the city's Commanders; Qin Nansheng was the only survivor of the six-person team. 15

The city possesses mineral veins, a Life Spring, an underground hall, and the Heaven's Gate Tree. These resources and infrastructure make it a major target in the conflict with Hope City. 146

Story Role / Major Arcs