Duel on Susevfi

Near the end of the Clone Wars, a Jedi strike team traveled to Susevfi and attempted to turn a band of Sith cultists back to the light side of the Force. The cultists rebuffed and attacked them. The Jedi slew the Sith, but Jedi Master Nejaa Halycon was mortally wounded.

Prelude
During the Clone Wars, Count Dooku converted Tyris to his cause with the promise of letting him access a Sith holocron Dooku had stolen from the Jedi Temple. This holocron had been one that the famous Anzat Dark Jedi Volfe Karkko often accessed.

The duel
Some time after the Battle of Praesitlyn, three Jedi found the training camp and the nascent Jensaarai. Nejaa Halcyon, Ylenic It'kla (who referred to Tyris as Nightsweat), and one It'kla called "Desertwind" attempted to turn the Dark Jedi from their path, but were rebuffed. Attacked, the Jedi squared off against Tyris and his companions and battle was joined. "Desertwind" managed to kill his opponent, the apparent leader of the Jensaarai, and Ylenic slew the Dark Jedi he identified as "Dustrose".

Halcyon, however, was less fortunate than the others. Tyris took advantage of Halcyon's lack of telekinetic powers and ran him through. Before succumbing to his injuries, Halcyon drained the energy out of Tyris's lightsaber and used the Force to break every bone in his body, killing him. The release of dark side energies at the deaths of the three Jensaarai leaders collapsed the structure where the rest of the Jensaarai were dwelling, killing all but four of the apprentices. The survivors included the wife of one of Tyris' apprentices, the woman who would later become the Saarai-kaar of the Jensaarai.

Aftermath
The Saarai-Kaar rebuilt the Jensaarai, but were unable to comprehend the Sith writings of Larad Noon, and developed practices that only skirted the dark side of the Force without embracing it. The Jensaarai would eventually become allies with the Jedi Order, and would be considered as Gray Jedi by the New Jedi Order.

Appearances

 * I, Jedi