Exar Kun's lightsaber

The lightsaber of Jedi Knight Exar Kun was a device that was initially created to produce a single beam of blue-white energy. However, upon his ascension to Dark Lord of the Sith, Kun redesigned his lightsaber based on instructions hidden within an antiquated Sith holocron. The finished product was a double-bladed weapon imbued with dark side energy, from which sapphire blades materialized up to 1.5 meters from either end of the hilt.

Kun wielded the single-bladed version of his lightsaber during his time as a student of Jedi Master Vodo-Siosk Baas, and with it, he earned a reputation as one of the galaxy's greatest lightsaber duelists. The modified, double-bladed saber that heralded his rise as Dark Lord of the Sith was revealed a year later, when Kun confronted and slew his former Master with it on the floor of the Galactic Senate Hall on Coruscant. With Kun's own defeat at the end of the Great Sith War, his lightsaber was lost on Yavin 4, only to be rediscovered decades later by an agent of a secret covenant of Jedi bent on the eradication of all things Sith. Quarantined and preserved for a time in the Sanctum of the Exalted on the planet Odryn, Kun's infamous lightsaber was among the Sith artifacts pillaged by the bounty-hunting Moomo Brothers, and it changed owners several times before it was eventually returned to the protection of the Jedi Council.

Text and facts from the “Exar Kun's lightsaber/Legends” article on Wookieepedia, licensed under CC BY-SA 3.0. Modified for this site.