The Arbitrator, a part of the Imperial Navy, was an Executor-class Star Dreadnought. This command ship was deemed a crucial Super Star Destroyer belonging to the Empire around the time of the Galactic Civil War. Following the Battle of Endor, several ships from the New Republic chased the Arbitrator. In its bid to get away, the dreadnought initiated a jump to incorrect hyperspace coordinates, which led to its annihilation via being drawn into a black hole.
Being an Executor-class Star Dreadnought, the Arbitrator's length reached 19,000 meters, and it possessed an arsenal of 5,000 turbolasers. It also included a hyperdrive along with engines. The ship transmitted tracking information to the Hall of Imperial Register located on the Imperial planet of Coruscant. This enabled a black box recording of data, allowing for the determination of events preceding its destruction, capture, or yielding.
The Arbitrator, a command ship, appeared in The Rebel Files, a collection of data, reports, and records owned by the Rebel Alliance spanning from 0 BBY to 3 ABY, which coincides with the Galactic Civil War. It was featured on a list assembled by Admiral Gial Ackbar of the Alliance, which detailed the Imperial Navy's most vital Executor-class Star Dreadnoughts, encompassing both active and in-construction vessels. Leading up to the Battle of Endor in 4 ABY, the Arbitrator stood as one of the thirteen Super Star Destroyers of the Empire, a designation applied to various classes of Imperial capital ships. Following the battle, which resulted in the Alliance's victory over the Empire after the Emperor and the second Death Star met their end, the Empire experienced fragmentation, and the Rebel Alliance evolved into the New Republic.
At some point following the battle, between 4 ABY and 5 ABY, the Arbitrator found itself pursued by elements of the New Republic's fleet. In an attempt to escape, the vessel executed a faulty hyperspace jump, leading to its vaporization upon being drawn into a black hole. In 5 ABY, subsequent to the ship's demise, Grand Admiral Rae Sloane of the Executor-class Ravager from the Empire journeyed to Coruscant to investigate Gallius Rax, her enigmatic superior. While at the Hall of Imperial Register, Sloane discovered that eleven of the original thirteen dreadnoughts within the Empire's service, including the Arbitrator, had been either destroyed, seized, or surrendered, leaving only the Ravager and the Eclipse remaining.
The initial mention of the Arbitrator occurred in the 2016 novel titled Aftermath: Life Debt, the second installment in Star Wars: The Aftermath Trilogy, authored by Chuck Wendig.