Imperial Civil War
this is one of the name given to the period of post-Palpatine Imperial history during which various Imperial factions fought for control of the Empire's remnants. It occurred shortly after the death of Grand Admiral Thrawn, and culminated in several Imperil factions assaulting the planet Coruscant and trying to gain control of it amongst themselves. The war ended with the emergence of the cloned Emperor Palpatine from his hiding place on Byss.