Darth Massikus

 was a Sith Lord who lived in the Umbaran Sith Temple, despite not actually being a Shadow Assassin. He, along with Talzin and Varad Zagg, was one of the de facto heads of the Temple. Massikus lived for generations by using the Binding to transfer his consciousness into different host bodies, including Ganner Slarwalker and Yula Ardinn.

Early history
Massikus claimed to be generations old, but by the time of the Clone Wars, few records remained of Darth Massikus' origin, and little was known other than that he had ties to Dathomir. It was unknown when or how long he had been with the Shadow Assassins for, but by the time of the Umbara mission he had already been working with Talzin, Varad, and Arek Saris for a long time.

The Binding of Ganner Slarwalker
The first time Massikus encountered Ganner Slarwalker was actually during his Jedi Trials. He sensed Ganner as a potential host, but was warded off by Sen Qorbin.

Years later, the two would meet again on Umbara, where Ganner sacrificed himself to buy his allies time to escape. Ganner was captured, and Talzin performed The Binding to allow Massikus to possess him. Unusually, Ganner's consciousness managed to survive the ritual, but Massikus decided it was irrelevant as he was still in control. Massikus proceeded to use Ganner's body to kill Tyrral Thraxton and Bail Malakath, but his control weakened with each kill. He chased Yula Ardinn, the remaining Jedi, to a temple on Dantooine but was beat there by Arek Saris who believed him to be dead. He interrupted their duel to finish Yula off, but Ganner overpowered him. Taking advantage of this momentary indecisiveness, Saris wounded Ganner before fleeing along with Yula.

Galen Slarwalker came to Ganner's rescue, managing to enter Ganner's consciousness to help him drive off Massikus' spirit.

Into the Shadows
While Massikus' spirit was now without a body, since he had not been technically killed, Talzin was able to bring Massikus to life once more by binding him to the body of Yula Ardinn, not long before Ganner's return to Umbara. He fled during the battle in search of his apprentice, leading Ganner to search for him after the battle. Eventually, Massikus decided to finish Ganner off once and more all and found him residing on Carlac.

Final Duel
Over the year leading to the final battle, Massikus allied himself with the Death Watch. On the day of the duel, Massikus had them attack the village Ganner watched over in order to lure him out. The bait worked, though Ganner defeated the Death Watch forces, and the two began their final battle. To Massikus' dismay, Ganner spent much of the duel retreating and stalling, leading Massikus into traps that weakened him. He revealed himself to be Yula, stunning Ganner and granting Massikus the minuscule advantage he needed to defeat Ganner, pinning him against a wall without his weapon. However, just as he went in for the kill, Galen incapacitated him, and Ganner entered Yula's mind to free her. This time, instead of simply expelling Massikus' spirit, Ganner took Massikus into his own body, effectively performing the Binding on himself. The two struggled for control, but Ganner overpowered Massikus long enough to activate his lightsaber and stab himself in the heart. Having finally died in a possessed body, Massikus was finally truly defeated.

Legacy
Although she did not keep her memories of his possession, Yula was shaken from her experience with Massikus and eventually decided to leave Galen follow her own path, setting in motion a series of events leading to the Binding of Ganner Slarwalker. Decien later learned of Massikus from Varad Zagg's journals, and his suspicious of Massikus' death were later confirmed after he discovered that Ganner had perished on Carlac and reasoned that Massikus must have died too.

Personality and traits
Massikus was a rather concieted Sith (though often justifiably due to his power) who frequently taunted his opponents during battle. He viewed very few as being equal to him; Talzin was the only true exception. He was constantly looking for potential host bodies to sustain his spirit, but did not care at all about who originally inhabited them. He also enjoyed toying with his kills to some amount, spending months slowly hunting down Tyrral Thraxton, Bail Malakath, and Yula Ardinn.

Powers and abilities
Massikus was a very powerful individual, having absorbed the power of the countless bodies he had possessed. He was the only individual who was able to overpower Ganner Slarwalker after he learned the truth of his power, very nearly killing him. When Massikus was trapped inside Ganner's body once more, he still presented enough of a challenge to force Ganner to commit suicide to prevent him from harming anyone else.

Behind the scenes
Darth Massikus did not appear whatsoever in the first two drafts of LOTF, with his role being fulfilled instead by Darth Maricus. His backstory will also be revealed later on into the series.

Appearances

 * LOTF: Ganner Slarwalker (first appearance)
 * LOTF: The Hunted
 * LOTF: Resurgence (mentioned only)