Yi Jeong Martial Academy was a sprawling estate hidden within the mountains.

Built in the classic architecture of the Central Plains, it was a maze-like manor surrounded by walls, a design originally developed for defense due to the community-based warfare unique to the region. A notable feature of such architecture was its doorways: general passageways were round openings without doors, accessible to all—except for servants. Servants had their own small, discreet side doors, placed in out-of-the-way locations to remain out of sight. Where a main gate was present, permission was required to enter, with the gate's size symbolizing the authority …