Long ago,  dokkaebi  and humans coexisted in the same world, working together to subdue monsters and maintain balance. But on the night the full moon rose, when the call from the heavens reached them, the  dokkaebi  were destined to leave humanity's side. Before departing, they sealed their power within masks and entrusted them to humans. These masks became both a contract between  dokkaebi  and humans and the legitimate means to govern supernatural beings.

〈Mumyeonggjrokbu〉 is an urban fantasy isolation novel born from this imagination. It reinterprets Korean folktales, myths,  dokkaebi  lore, and ghost stories through the lens of a modern isolation narrative. Weaving together past and present, this work creates a multilayered world where players confront the precarious balance between humans and supernatural beings through investigation and documentation.

The containment corporation is composed of four departments:
Yangban Mask External Mediation Bureau ,
Chorang-i Mask Secret Containment Division ,
Lion Mask National Disaster Response Agency ,
Imugi Mask Capital Management Bureau.

This organization adopts traditional Korean painted masks as its symbols, with each department fulfilling its designated role and function.

Containment levels—Mang, Hyeon, Choseung, Geumeum, and Sak—indicate the danger level of each contained entity. The Tal are used to classify, contain, and manage these anomalies according to their risk.