In the year 3640 BBY, amidst the Galactic War that raged between the Galactic Republic and the Sith Empire, the forces of the Empire launched an assault on Ruan, a Republic agriworld, unleashing an orbital bombardment. The Imperial Navy, under the leadership of Moff Nezzor, inflicted severe damage to Ruan's agricultural infrastructure, resulting in the deaths of numerous Republic civilians and personnel.
Following a bombing attack on the Orbital Defense Command Center located on the planet of Ziost, which nearly resulted in the death of the Minister of Logistics, Davidge, the Dark Councilor Darth Marr commanded the Minister to initiate further attacks. The goal was to revitalize the Sith Empire's offensive capabilities within the ongoing Galactic War against the Galactic Republic. Davidge received additional instructions to utilize Moff Nezzor, a figure whom Davidge considered an unprofessional sociopath. Consequently, the Minister was compelled to allocate resources to Nezzor's endeavors. The Republic Strategic Information Service became aware of the impending assault on Ruan through the use of a black cipher. This secure encryption device, belonging to the Empire, had been acquired during the attack on Ziost. However, Supreme Commander Jace Malcom opted to withhold assistance from the agriworld in order to safeguard the Republic's possession of the cipher.
Nezzor's fleet, having penetrated deep into Republic territory, launched an attack on Ruan. This agriworld supplied the Republic's capital, Coruscant, with essential foodstuffs and was situated within the same sector as Coruscant. The Imperial forces swiftly eliminated the local Republic fleet before commencing a devastating orbital bombardment utilizing capital ships. This assault resulted in the destruction of the majority of surface production facilities and the deaths of thousands of civilians, marking a significant triumph for the Empire.
Nezzor, emboldened by his triumph, subsequently attempted an attack on Duro, a world known for its shipbuilding capabilities. The Imperial Ministry of War then leveraged the battle in its propaganda campaigns in order to reassure the citizens of the Empire that they were not on the losing side of the war.
The Battle of Ruan was initially referenced in Chapter 11 of The Old Republic: Annihilation, a novel published in 2012, when Darth Marr instructed Minister Davidge to employ Moff Nezzor. Furthermore, Theron Shan observed news reports concerning the battle over a week later while infiltrating the Imperial outpost known as Reaver Station.