One month prior to the liberation of Kashyyyk, the forces of the New Republic launched an assault on the Imperial-controlled Hyborean Moon, resulting in the destruction of both the ISB's clandestine detention facility and adjacent residential areas.
During the Age of the Empire, the Hyborean Moon served as the location for a secret Imperial prison complex. Agent Romwell Krass Junior of the Imperial Security Bureau considered the Hyborean Moon a desirable assignment for his family. Krass, along with his family, resided in a comfortable dwelling situated on the banks of a thermal spring lake. Furthermore, he facilitated the transfer of his associates to the same location.
Following the Battle of Endor, the Rebel Alliance reorganized into the New Republic. The New Republic then deployed a fleet with the purpose of engaging and defeating the Imperial forces stationed on the Hyborean Moon. The civilian infrastructure was targeted by New Republic starships, resulting in the death of Krass' family. Krass narrowly escaped aboard a starship as rebel forces invaded and seized the prison.
For a month following the attack, Romwell Krass Junior wandered aimlessly through space, mourning the loss of his family. He developed a dependence on alcohol and began to excessively consume it. Instead of reporting for duty to the Imperial capital located on Coruscant, Krass journeyed to Maz Kanata's castle situated on the planet Takodana. While there, he became embroiled in a physical altercation with a New Republic pilot. The fight was intervened upon by Maz Kanata's droid ME-8D9, who subsequently confined the two combatants within Maz's dungeons. Maz ultimately released them, but advised Krass to find peace regarding his grief.
A brief mention of the Attack on the Hyborean Moon appears in Chuck Wendig's 2016 novel entitled Aftermath: Life Debt, which constitutes the second installment of The Aftermath Trilogy.