As flagship, Vengeance led the Imperial Task Force Vengeance into the Airam sector to pacify it and quell a Rebel Alliance expansion. Their opposing campaigns were known as Task Force Vengeance and Spreading the Rebellion, respectively. Combined, they became colloquially known as the Balance of Power campaign.
The Rebels wore down the task force with a series of surgical strikes and by attacking their supply lines. Eventually, Admiral Senn attempted to force a victory by launching an all-out attack, spearheaded by the Vengeance, against the Rebel stronghold in the Nocto system. During the ensuing Battle of Nocto the rebels and their Airam allies rammed three suicidal Dreadnaughts filled with explosives into the Vengeance from the rear. A CR90 corvette, the "Thunder" rammed the bridge of the Vengeance completely obliterating it. Finally, A heavy bomber strike carried out by B-wing starfighters was sufficient to bring down its deflector shields destroying the dreadnought.
Although there are conflicting reports on the outcome of the battle, both the Vengeance and the Rebel shipyard Calenz are thought to have been destroyed in this battle.
Within the game itself, Vengeance had a length of eight kilometers, which at the time was considered canon for the Executor-class. However, Star Wars: X-Wing vs. TIE Fighter: Balance of Power Campaignss cover art depicts it as a substantially larger ship, in line with the nineteen kilometer length that is now canon.
The understated length suggests that Vengeance may have been one of the very first lot of four Executor-class warships commissioned by the Emperor prior to the Battle of Yavin, but The Essential Guide to Warfare lists the Executor, the Reaper, the Aggressor and the Brawl as the first four ships of that class, and never mentions the Vengeance. Additionally, The Essential Guide to Vehicles and Vessels asserts only four Executor-class Star Dreadnoughts were known to have been in service to the Empire by the time of the Battle of Hoth in 3 ABY.
Nevertheless, since first mission to Almaran was performed by the Alliance shortly after the Battle of Hoth, Vengeance was probably the fifth or the sixth Executor-class warship manufactured for the Empire, and the second such ship completed at the Fondor Shipyards—the first being the Executor.
The Dark Jedi Jerec operated another SSD named Vengeance several years later, but it appears to be of an entirely different design, being much sleeker than the Executor-class.
It is somewhat arbitrary whether the destruction of the SSD Vengeance is canonical. The Balance of Power add-on to the X-wing vs. TIE Fighter game, the only source featuring this ship, comes with a campaign for both sides, the Empire and the Rebellion. Both campaigns culminate in the same battle where the Vengeance leads an all-out attack against a Rebel shipyard. When playing the Rebel side, the last mission's objectives are to prevent the destruction of the shipyard and destroy the Vengeance while the Imperial mission objectives are reversed. If the player successfully concludes the Imperial campaign, the shipyard is destroyed while the Vengeance is not.
However, the destruction of both SSD Vengeance and the Rebel shipyard do not cancel each other out; it could be argued that all missions and cutscenes from Balance of Power are canonical, including the ultimate simultaneous destruction of the shipyard and the SSD Vengeance. This would be the smallest possible tweak to the available information and also fit in with the apparent general consensus that the Empire and the Rebellion achieved a draw in the Airam campaign by essentially wiping out each other's forces. Neither the SSD Vengeance nor Admiral Senn are ever mentioned again afterward.
- The Complete Star Wars Encyclopedia