Jedi were Force-Sensitive members of the noble Jedi Order of protectors, who studied, served and used the mystical energies of the Light Side of the Force. The weapon of the Jedi was the Lightsaber, a weapon fueled by kyber crystal with a blade of pure energy which have various colors. The Jedi fought for peace and justice in the time of the Galactic Republic, usually against their mortal enemies, the Sith and fallen Jedi, who studied the Dark Side of the Force. The Jedi were of ancient origins, having been present in the galaxy for over one thousand generations. By the time of the Clone Wars there were ten thousand Jedi n the galaxy, but by the end of the war, they were all but destroyed by the Sith during and after the execution of Order 66. After the Jedi Purge, few Jedi managed to survive, with only one Jedi living by the end of the Galactic Civil War, Luke Skywalker. Skywalker rebuilt the order in the years after the Galactic Civil War into a New Jedi Order, but his nephew and apprentice Ben Solo, later dubbed Kylo Ren, massacred all of its members, leaving Skywalker once again as the last remaining Jedi.
The Jedi Order, later known as the Old Jedi Order and referred to as the Holy Order of the Jedi Knights, was an ancient monastic peacekeeping organization unified by its belief and observance of the Lights Side of the Force. The Jedi were the guardians of peace and justice in the Galactic Republic, and became perhaps the most well known of the various groups that relied on the Force for their power. Led by a series of Jedi Councils, the Order grew over the millennia despite facing many trials. As mystical wielders of the Force and of their signature lightsabers, their powers inspired all citizens in the galaxy. The calm, considered demeanor of the Jedi made them ideal brokers of peace in times of conflict or dispute. Yet, for all their power and diversity, the Jedi were often beset by foes in times of doubt and confusion, the most notable of which being the forces of the Sith. These dark warriors were the antithesis of the Jedi, their sworn enemies, and the battle between them brought the galaxy to war more than once.
The New Jedi Order was a restored and reformed Jedi Order, in the wake of the Great Jedi Purge and subsequent fall of the Galactic Empire. The Jedi Knights, reduced in number to only a handful, were slowly restored, primarily under the leadership of Luke Skywalker, son of the former Jedi Knight Anakin Skywalker. Among Skywalker's students was his nephew Ben Solo, who was the son of his sister Leia Organa and the famed smuggler Han Solo. Ben, however, was seduced by the dark side of the Force at the coaxing of Snoke, an enigmatic figure who spearheaded the Imperial-inspired First Order, and took on the name Kylo Ren, joining the ranks of the Knights of Ren. The new generation was betrayed and destroyed by Ren at their Jedi Temple, and Skywalker, feeling responsible, went into exile following the massacre.