The Shadow Knights of Quary were a force based organization. They called themselves a Sith organization because they still lived by the Sith code, but they didn't use the Dark side of the force anymore. They lived and operated on Quary. The group trained Force-sensitives who were too old or too weak to be trained by the Jedi order on Urum. Shortly after the Force wars on Quary, they started taking the DNA from creatures, which were extinct because of the wars. They cloned the creatures, and used a few to ride on, the rest which had no use were send into nature.
At the end of the Force Wars on Quary, the Sith and Jedi, except for the Gray Jedi who didn't want to fight, launched massive stone storms at each other. The storms became unstoppable. A few Sith fled into a cave, all of the Sith and Jedi on the battlefield died. Almost the entire worlds surface was destroyed. Because of this the surviving Sith swore never to use the dark side again and never to use Force stonestorm again. Due to the wars they had to live in hiding. they took the DNA from extinct creatures, cloned the creatures, and used a few species to ride on.
After spending 500 years in hiding they began to train all Force-sensitives who weren't allowed to be trained in the Jedi temple. Their numbers grew fast, and after a while they were ready to send people out to fight crimes.
In the Uruniun war they saved Snie and his men who were looking for them to make an alliance. At first they weren't sure, but after discussing it on their counsel they approved to fight the Empire. After the war they built their own temple and were allowed to do the Jedi's job on Quary.
Because the Knights were all Quarians the Knights culture and that of the quarians had a lot in common. The Knights rid on the same creatures as their ancestors did, they breded them themselves because many creatures died during the stonestorms and they were very rare. they had a headquarter in every province of the planet.
Every 25 years a new leader would be chosen, he would be given the name "Great one". their would be several rounds. In the first round they would prove their strength by killing a giant, in the second round they would prove their speed in a running test and in the third round they would prove their wisdom. Every knight above the age of 21 years would then decide who would be the next leader. A person was allowed to be chosen "Great one" 2 times in his life, but this rarely happened. Till 500 BBY there was a fourth round in which the best men would fight each other and the surviving knight would become the "great one", but the winner in 500 BBY decided that the fourth round had to be deleted from the trials.
Shadow Knight ranks
Great one - This title was given to the leader of the Knights, the strongest, the fastest and the wisest.
Master Knight - The title given to the members of the counsel.
High Knight - The title given to a person ready to train someone else.
Knight - The title when you finished the trials.
Young Knight - Someone in training.
Fast shadow - Given to the fastest Knights.
Strong shadow - Given to the strongest Knights.
Wise Shadow - Given to the wisest Knights.
If a Knight had all tree medals he was allowed to participate in the Fight for Leadership.