Jedi
A Jedi, also known by the title of Lord Jedi in ancient times, was a devotee to the ways of the Jedi Order, an ancient order of protectors united by their ability to harness the power of the Force. Adhering to a doctrine that favored the light side of the Force, the Jedi aspired to attain a state of inner tranquility through calmness and meditation while avoiding emotions affiliated with the dark side of the Force, such as anger and hatred. Nevertheless, Jedi philosophy did not forbid a Jedi from acting in self-defense or in the defense of others. To that end, the weapon of a Jedi was the lightsaber, a blade composed of pure energy and different colors such as blue, green, purple, or yellow.
When a rogue Jedi was exiled from the order after advocating the use of the dark side of the Force, they gained followers which led to the creation of the Sith during the Hundred-Year Darkness. The Jedi and Sith became bitter enemies, engaging in a number of battles and wars like the Sith war, the Battle of Takodana, the Great Hyperspace War, the Great Scourge of Malachor, the Great Sith War, and the defeat of Darth Momin.
Another splinter group of Jedi emerged, calling themselves the Ordu Aspectu. Some records suggested they had hoped to give immortality to everyone in the galaxy, yet others believed that they may have killed Jedi Padawans to try to achieve their goals. Nevertheless, the Jedi and Ordo Aspectu came to fight against each other in the Entruvia Conflict and the doom of the Ordu Aspectu, the latter conflict resulting in the defeat of the splinter order. However, the leader of the Aspectu—a man named Rur—was able to download his mind into a computer, creating the Eternal Rur. At another point in the Jedi Order's history, in the aftermath of the Corsair Wars, Jedi Master Oo'ob broke from doctrine to create the Farkiller.
Also during the reign of the Old Republic, the Mandalorians, the warrior people of the planet Mandalore, launched a number of wars, often coming into conflict with the Jedi. Battles between the Mandalorians and Jedi dated back to the time of the Mandalorian crusaders. According to legend, Mandalore the Great led the Mandalorians against the Jedi in a number of battles. Eventually, the Mandalorians developed their distinctive armor in order to combat their Force-sensitive enemies.