Darth Sentinel

Darth Sentinel was a strange hybrid Sith, composed of an Anti-Air Turret with the mind of Jor Drakas. He formed the Mounted Killers gang before disappearing, then reappearing in a clone Twi'lek body. He was then prone to lycanthropic changes due to the corrupt nature of his body and killed the gang before being killed by Desann.

History
Jor Drakas, a Twi'lek Jedi Knight, was assigned during the Clone Wars to hunt down and kill Count Dooku's general, Sev'Rance Tann. After she evaded him at the Kyar Orbital Platform, he managed to track her to the lava world of Sarapin, but in a lightsaber fight with her, was defeated and kicked into a nearby lava river. Using his telepathic powers, his Force form managed to escape his body right as it burned up. It sat, unable to move, for years on the bank.

Later, in about 1 BBY, the Rebel Alliance fortified Sarapin to fight the Empire. When a TIE squadron swooped over to scout the Rebel base, they set up an Anti-Air Turret to protect the base--right where Drakas' Force body was. Therefore, his body was trapped in the turret and it became his new body. Obviously, the horrific experience immediately took a toll on Drakas and he went mad. He used his Force powers to alter the metal of the turret and it transformed into a humanoid body. He declared himself "Darth Sentinel" and the Dark Lord of the Sith, unaware of his former Chancellor's transformation into the Dark Lord. He decimated the Rebel base and escaped Sarapin, mysteriously disappearing. A few years after the destruction of the first Death Star, reports came of a huge machine that would destroy cities and bases, Imperial and Rebel alike. Both forces looked into it but came up with nothing.

Sentinel again appeared with clones of various bounty hunters, including Greedo, Jango Fett, Aurra Sing, and Durge, forming the clones into the "Mounted Killers" gang. They were called this because they often appeared on mounts, including Boga (Obi-Wan Kenobi's varactyl, who actually survived her wounds from the Battle of Utapau), Yoda's kybuck (stolen from the ruins of the Jedi Temple), and speeder and swoop bikes. The gangs committed robberies (as they were brainwashed away from their usual bounty-hunting by Sentinel) before the entire roster except for Darth Sentinel himself was wiped out by Stormtroopers. Darth Sentinel vanished shortly thereafter.

Return of the King
Darth Sentinel returned in a new body, cloned from the brain matter of Bib Fortuna, now a Bo'marr Monk in 6 ABY. He claimed the Imperial Remnant (which Kyle Katarn would face later) had destroyed his turret body, so he built a clone one. He made a red lightsaber on Ilum and attacked Coruscant with hopes of killing Chief of State Mon Mothma, but the attack failed and he was driven back. He vanished again into the depths of the galaxy.

Death
Truly no longer sane at all, the being who was once Jor Drakas attacked Luke Skywalker's Jedi Praxeum on Yavin 4 in 10 ABY. However, his attack again fell on its face--literally--when he tried to sneak up on and kill Skywalker. He tripped over his own feet and was then cut down by Desann. Analyzing his body, Luke was horrified to learn that Darth Sentinel was Master Drakas, an old friend of Obi-Wan's. He gave Drakas a proper burial on Yavin 4, and Darth Sentinel was never heard from again.