These are events that followed the Rebellion's victory over the Empire.
After defeating Emperor Sheev Palpatine and destroying his ultimate weapon, the planet-killing Death Star, the Rebellion's most senior members founded the New Republic. Mom Mothma was appointed Chancellor of the new Senate. To Luke Skywalker, Jedi Master, he was given permission to rebuild a temple and train a new generation of Jedi.
Traitors, senior members of the Empire, were hunted down and condemned for their crimes.
The first years were difficult, but over time, the wounds of the past seemed to heal little by little.
And then one day, out of nowhere, they came.
From a place unknown to all, thousands of starships entered the galaxy, and declared war on the Republic.
They weren't humans, or beings of any known species. They were droids of a kind we had never heard of. Powerful, intelligent, perfectly adapted to all types of combat... Even without the slightest living being at their side, they were capable of waging a war and winning.
But there was a different being among them. Their boss. Nobody really knew anything about him. It was a Shadow. Locked behind a mask, like a skull, painted red and white. He was covered with an immense black cape; the only thing sticking out of it was some kind of arm, obviously as black as darkness, and on the end, a lightsaber, glowing with red light.
As I said, the power of this new enemy was insane.
And even with all the forces of the Republic, of this powerful group that had defeated the Empire, nothing was enough to stop this new enemy. And many heroes of ancient wars, such as Admiral Ackbar, or President Mothma, died.
Eventually, Luke Skywalker went to confront the Shadow himself. Once again, a Jedi pitted against a Sith.
But Master Skywalker was defeated. No one ever heard of him again, and we can only assume today that he is dead.
Today, the Galaxy is dominated by this Shadow - of which we now have a name: Darth Nihilus.
The droids control every village on every planet in every system.
All hope seems definitely lost.
Unless the hope, precisely, is called Nobody.