Not every Jedi perished in Order 66. Kanan Jarrus survived the Emperor’s purge, going underground for years and hiding the truth about who he really was. To keep his past a secret, Kanan carried a blaster -- an uncommon practice for a Jedi -- and used a lightsaber that had to be assembled. He was a leader among the Ghost crew, a small group of rebels looking to strike back against the Empire, and with the emergence of the Force-sensitive Ezra, once again embraced his identity as a Jedi Knight.
At the heart of every Jedi lightsaber is a kyber crystal found on several planets, most notably the icebound caves of Ilum. This crystal is attuned to the Force, and connected to a Jedi Knight on a deeply personal level. In this way, a lightsaber is an extension of a Jedi's Force awareness. Because Jedi let the Force guide their selection of the crystal, the vibration that the crystal creates in the lightsaber blade helps Jedi center themselves and find balance in the Force. In this way, a Jedi can center his or her attention beyond the distractions of combat. A lightsaber crystal is colorless until first attuned and connected to a Jedi -- at which times it glows either blue or green, or in some rare instances, another shade. From that point on, it retains that hue.
Not much is known about the Empire’s Grand Inquisitor. A Pau’an male, he was tasked by Darth Vader to hunt down any surviving Jedi Knights. The Inquistor was an intimidating figure, dressed in all black and wielding a red, double-bladed lightsaber. After several encounters with Kanan Jarrus and his Padawan Ezra Bridger, the Inquisitor died in a lightsaber duel with Kanan – but warned the rogue Jedi that his victory had unleashed something terrible.
The Grand Inquisitor, the Empire's ruthless Jedi hunter, carried a lightsaber built to destroy. The weapon featured dual modes, crescent and disc, in addition to some deadly surprises. In its crescent setting, the lightsaber had a single red blade; in disc mode, a second blade emerged, and a spin feature turned the lightsaber in a blindingly fast killing tool. The Grand Inquisitor relished combat, and his weapon proved very effective at intimidating, disorienting, and dispatching his enemies.