Mecrosa Order The Mecrosa Order was a group of assassins that served the Tapani sector ' s noble House Mecetti . Possessing a long history , the Mecrosa Order was closely linked with the Sith and the dark side of the Force . History . Founded during the Tapani sector ' s Dynastic Era , the Mecrosa Order began as a group of Force - sensitive nobles of House Mecetti who swore an oath to protect the House with their lives from all who threatened it . Based within an ancient castle on the planet Nyssa , the Order grew in wealth and numbers as House Mecetti remained stable and strong . Establishing chapter houses across the surrounding systems , the Order established an elaborate network of spies and informants to keep the flow of information open at all times . During this two hundred year period of growth and expansion , the Order began to be corrupted from the inside , coming under the scrutiny of members of the Jedi Order that were sired by the rival House Pelagia . Accusing the Mecrosa Order ' s leader , Viscountess Mireya of Vjun , of consorting with Sith holocrons and dabbling in the dark side of the Force , even allowing Sith Lords to own tax - free holdings on Nyssa . During the time known to history as the Old Sith Wars , under the leadership of High Lady Brezwalt III , the Mecrosa Order began funding the devastating conflict led by Sith Lord Exar Kun , which garnered a strong response by the Jedi . To counter the Sith supporters , the Jedi Order embarked upon a massive purge of Sith teachings in the Tapani sector , declaring the pogrom the Cleansing of the Nine Houses . While the Jedi were successful at killing most of the Sith - leaning members of the Order , the Mecrosa survived in secret within the Tapani sector , though many of the survivors were not Forceful . Abandoning the use of Sith teachings and poisons , the Mecrosa sought out frinka venom and learned the skills of various martial arts . However , the assassins of the Order were trained to survive toxic atmospheres , poisons , and sicknesses by taking chemical cocktails to immunize themselves to the effects . By the time of the Cold War , the Order was still fragmented , and their databases vulnerable to outside infiltration . As the secret society recovered over the next four millennium they became especially thoughtful in regards to who gained membership . The Mecrosa did not play a part in the wars between the Jedi and Sith for some time until the New Sith Wars and fell in with the New Sith Empire . Despite their pledged loyalty , the Order was responsible for the poisoning of Sith Lord Belia Darzu in retaliation for her intrusion into the Tapani sector in 1230 BBY . A thousand years later , the weakened Order was tested by the leader of the Dathomirian Nightsisters , Mother Talzin . Sending three shadow killers to the Pella system in search of rival groups , only one Nightsister fell while all Mecrosa combatants died . Several years later , Sir Nevil Tritum was part of the reinvigorated Mecrosa Order under the Galactic Empire . Tritum , while not Forceful himself , recovered the lost holocron of King Adas from the library of House Pelagia , killing three Jedi Guardian s in the process . The Order would remain silent during the Galactic Civil War , reappearing once more after the death of the Galactic Emperor . At this time the Order was led by Lady Estalle Balis , the director of House Mecetti ' s very effective spynet . Sometime after the battle over Endor , the Mecrosa were visited by former Emperor ' s Hand Lumiya . Requesting that the Order allow her into their vaults , the Mecrosa felt obligated to assist her in her pursuit of knowledge and grudgingly allowed her access .