This is the immediate aftermath of Return of the Jedi: the second Death Star has been destroyed over Endor, Emperor Palpatine and Darth Vader are dead. Now what? A whole bunch of books and comics, mostly.
The Rebel Alliance quickly moves to capitalize on its victory by formally dissolving shortly after the Battle of Endor and reforming as the New Republic, bringing a legitimacy to its claim to lead the galaxy in the wake of the Empire’s chaotic fragmentation without leadership. The heroes of the original trilogy of movies also disperse their separate ways: Luke begins searching for Jedi and Sith artefacts hoarded by Palpatine over his life, seeking a better understanding of the Force and his place in it, while Han and Leia, married on Endor after the battle, find themselves tasked by Mon Mothma with an interplanetary Disney World vacation aboard the Halcyon during the events of Beth Revis’ novel The Princess and The Scoundrel, travelling to different worlds where Imperial influence is still tenuous to convince people that the days of the Empire are truly over.
But just because the Rebels defeated Palpatine at Endor doesn’t mean the Galactic Civil War is actually over. Across the Aftermath trilogy of novels by Chuck Wendig, we see Mon Mothma, now instated as the first Chancellor of the New Republic—and the Senate is reformed on her homeworld of Chandrila—begin to enact a demilitarization pact that largely intends to break up the Alliance Navy into a much smaller New Republic Fleet, transitioning military matters to the planetary defence forces of Republic member worlds. Meanwhile the remnants of the Empire begin to launch counterattacks in the form of Operation Cinder, a posthumous plan created by Palpatine to sow chaos through strikes on select worlds either sympathetic to the Rebellion or problematic loyalist Imperial worlds through weather manipulation satellites.
As Warlordism sees several former Grand Moffs or major Imperial generals establish their own small fiefdoms, a larger Imperial Remnant begins to form out of a collective of short-lived councils of Imperial allies—first with the Imperial Future Council, which is largely eliminated during the liberation of the planet Akiva, and then the first Imperial Shadow Council…