Darth Gean Darth Gean was a Twi ' lek female who was apprenticed to Dark Lord of the Sith Darth Gravid , as part of the Order of the Sith Lords . Around 552 BBY , Gean learned that Gravid , who attempted to blend Jedi doctrines with his Sith teachings , was trying to destroy all the various Sith artifacts , tomes , and holocrons that contained Sith teachings . Gean penetrated the Force shields that Gravid had placed around the fortress that they had built together on the planet Jaguada and was able to kill her Sith Master . Nevertheless , during the fight , Gravid grievously injured Gean , which forced her to wear prosthetics . She eventually took an apprentice of her own , continuing the lineage instituted by Darth Bane . Biography . A Twi ' lek female was sensitive to the Force , eventually becoming the Sith apprentice of Dark Lord of the Sith Darth Gravid and taking the name Darth Gean . During her tenure as Gravid ' s pupil , Gean helped her Sith Master construct a fortress on the planet Jaguada . However , Gean ' s Master had begun to lose his sanity , because he attempted to combine Jedi philosophies , such as benevolence and empathy , into his Sith teachings . At some point around 552 BBY , Gravid — who had concluded that his repository of Sith holocrons and tomes needed to be destroyed so that he could rebuild the organization — used the Force to raise barriers around his fortress and began eradicating the Sith knowledge in his possession . Gean broke through the shields around the fortress and confronted her Master in a duel . During the fight , Gean was gravely injured after Gravid cleaved off one of her arms and shoulders as well as the left side of the Twi ' lek ' s face and chest . However , Gean gained the upper hand , killing Gravid despite being unarmed . After the confrontation , Gean acquired prosthetics to replace the limbs she had lost . She eventually took an apprentice of her own and continued with the Grand Plan — which was instituted by Darth Bane , the founder of the Order of the Sith Lords — to topple the Jedi Order and the Galactic Republic . In taking her apprentice , Gean continued the Rule of Two , an ordinance also instituted by Bane that restricted the Sith to a single Master and apprentice . Gean ' s eventual successor , Darth Plagueis , recounted her actions to his apprentice , Darth Sidious , believing her to be courageous . Personality and traits . After discovering Darth Gravid ' s plan to destroy the Sith teachings , Darth Gean displayed complete dedication to the dark side of the Force and the Sith Order by fighting and murdering her Master , despite being seriously injured in their duel . Powers and abilities . Darth Gean was sensitive to the Force and was powerful enough to break through her Master ' s Force barriers around his fortress . She was also able to survive the confrontation with Gravid , despite being grievously injured and being forced to wear prosthetics as a result . According to Darth Plagueis , the Twi ' lek ' s power with the Force was not obstructed on account of her cybernetics . Behind the scenes . Darth Gean was introduced in the 2012 novel " Darth Plagueis " , written by James Luceno . Her character was created to explain some of the background of the Order of the Sith Lords .