Eclipse II represented the second vessel of the Eclipse-class dreadnought line. It also held the position as the second flagship under the command of Palpatine.
The Eclipse II shared visual similarities with its earlier counterpart, the Eclipse, including its specific coloration. However, modifications were implemented in certain areas, notably the arrangement of the engine systems. Furthermore, a tower structure was added, positioned atop the axial superlaser.
The development phase of the Eclipse II occurred concurrently with that of the initial Eclipse, spanning from 0 BBY to 0 ABY. In contrast to the first Eclipse, the construction of the Eclipse II took place directly above Byss. Echoing the fate of its sister vessel, the completion of the Eclipse II faced delays because of Palpatine's passing.
Following the destruction of the original Eclipse, it became the primary flagship for Emperor Palpatine. The Eclipse II served as Palpatine's transport to the Sith planet of Korriban, and later played a central role in the Battle of Onderon, where the New Republic sought to capture the Emperor.
The Eclipse II met its ultimate destruction above Byss, an event triggered when the astromech droid R2-D2 gained control of its computer systems. R2-D2 then programmed the ship to collide with the Galaxy Gun. Upon impact with the orbital cannon, a projectile launched from the Galaxy Gun was drawn towards the planet below. The resulting explosion obliterated both the remains of the Star Dreadnought and the superweapon. This destruction, along with that of Byss, led to the deaths of many royal guards, leaving very few survivors, including Kir Kanos and Carnor Jax.