As the Pijali Princess Fanry's coronation neared in 40 BBY, Czerka Corporation and the Inner Rim planet Pijal's serving lord regent Rael Averross used the results of a census of the Pijal system's population to draft the Governance Treaty initiative, which would reorganize the reigning Pijali monarchy into a relatively powerless constitutional monarchy and cede power to a representative Assembly. However, Fanry felt that Czerka had been exploiting her world's citizens by unfairly enslaving them and did not wish to sign the treaty upon her crowning, hoping to retain her power as future queen. Averross, meanwhile, felt that the Governance Treaty would benefit Pijal by allowing the Assembly to open the Pijal Hyperspace Corridor hyperspace route in conjunction with the Galactic Republic.
Fanry and her royal guard captain Deren began secretly organizing a contingent of Pijali blackguard soldiers to carry out a campaign throughout the Pijal system, hoping to sow enough unrest in the system to prevent the treaty's signing. As one of those attacks, the blackguards used nanotech to dissolve the mirrors forming the framework of the Hall of Assembly—a building intended to serve as the Assembly's new headquarters—with each panel turning cloudy, then gray, then crumbling to dust.
Qui-Gon Jinn (right) and Obi-Wan Kenobi (left) investigated the upheavals in the Pijal system, including the Hall of Assembly's destruction.
In the aftermath of the event, many Pijali were confused about what had happened to the building, which had been intended to be a symbol of incoming democracy. The inquiry into the incident afterward eventually showed investigators holographic security camera footage displaying how nanotech had eroded the building from within.
The Hall of Assembly's destruction was blamed on the Opposition—a political performance troupe known for advocating against the Governance Treaty—and Deren stored a recording of the event. Some days later, Deren gave the Jedi Master Qui-Gon Jinn and his Padawan, Obi-Wan Kenobi, the recording of the Hall of Assembly's destruction while they were investigating several recent upheavals on Pijal. Eventually, following Fanry's unsuccessful attempt to crown herself queen during her violent coronation, the Opposition was cleared of blame for several of the blackguards' strikes, including the destruction of the Hall of Assembly.
The attack appeared in a hologram in Master & Apprentice, a 2019 novel written by Claudia Gray.