The battle on Eriadu's surface was between the Fel-loyal 501st Legion, led by Senior Commander Daine Jir and the Imperial Centre 3rd Army, which had retreated from Coruscant after it's capture and was led by the experienced commander Geist. During the battle Rulf Yage had been given command of the Skulls, Fehlaaur, the Nirauan 2nd Fleet. Yage's daughter, Gunn had also defected, alongside her elite starfighter wing, Skull Squadron. Most of Veed's insurgency had defected to Fel's side after the capture of Coruscant, meaning that Fel's forces had been bolstered by the First Imperial Strikeforce, led by Moff's Fehlaaur'aitel'loro and Rulf Yage. It was fought between forces loyal to the Fel Dynasty and the forces of Morlish Veed's insurgency who supported the Moff Council's rule of the Empire.
The Battle of Eriadu was the final battle of the Second Imperial Civil War. Heavy: many Stormtroopers, 26 Star Destroyers, many Starfighters, all senior commanders except Viktor Piard (Surrendered) & Geist (Defected)