Between approximately 1100 BBY and around 1000 BBY, the Sith Lord known as Darth Momin was compelled by the dark side of the Force to single out a city for utter annihilation. Aided by his acolytes, Momin engineered a superweapon with the capacity to obliterate the entire city. As the inhabitants became aware of their impending deaths, the superweapon initiated the city's gradual destruction. Subsequently, a number of battle-hardened Jedi managed to infiltrate the superweapon, and despite the formidable defense mounted by Momin's acolytes, their efforts proved insufficient. The Jedi's presence disrupted Momin's focus on the weapon, causing him to relinquish command over its engines. The superweapon discharged, instantly vaporizing the city. The resulting explosion led to Momin's demise, although his consciousness endured within his mask. Millennia later, on the planet of Mustafar, Momin recounted this history to the Dark Lord of the Sith Darth Vader.
Darth Momin, a Sith Lord by title, also held the vocation of a sculptor. He was imprisoned due to the disturbing nature of his artistic creations, only to be later liberated and trained by the Sith Lady Darth Shaa. Following killing Shaa, Momin journeyed across the galaxy, becoming consumed by the aspiration to produce art that would appease the dark side of the Force itself. The Force communicated with Momin, directing him to select a city. Leveraging resources inherited from Shaa, along with the assistance of his acolytes, Momin devised a superweapon of sufficient power to reduce the city to ashes.
Momin piloted the superweapon above the city, initiating its ruin. His scheme involved channeling the Force into the engine to decelerate the passage of time, thereby freezing the agonizing reactions of the city's inhabitants for all time, akin to insects preserved in amber. As the residents watched in terror, Momin's macabre artistic endeavor progressed, with the engine moving into position for the perfect stroke. However, two members of the Jedi Order intervened to halt his plan. Momin's acolytes engaged the Jedi in combat but were unable to mount an effective defense, falling to the skilled knights.
The presence of the light side of the Force disrupted Momin's concentration, causing him to lose control of the engine as the superweapon became engulfed in flames while the opposing forces exerted their power. Nevertheless, the weapon discharged, instantly obliterating the city. Momin, however, failed to capture the horror he sought to preserve in time through the Force. Momin's physical form perished in the conflagration, but his consciousness persisted within his mask.
More than a thousand years later, Dark Lord of the Sith Darth Vader transported the Momin mask to Mustafar. Upon claiming a new body, Momin recounted the events surrounding the city's destruction to Vader. Subsequently, Vader appointed Momin as the architect for Fortress Vader.
The city's destruction was initially depicted in a flashback within the 2018 canon comic Darth Vader (2017) 22. The comic was authored by Charles Soule and illustrated by Giuseppe Camuncoli.