The Sword Lords have earned their name from their interesting method of succession. Originally Restov was an outpost to serve the logging and mining communities in the area. As more people moved to the area, the city grew and the commander of the guard stationed there became overwhelmed by the logistics of trying to run a community. A particularly charismatic adventurer in the area saw an opportunity, and when he developed enough of a following he declared himself as the leader of the city. He challenged anyone who wanted to take the title from him to a sword duel. Several men challenged him, but as he was an accomplished swordsman none were able to take him.
Soon several dueling academies rose up to train those wishing to challenge him. None were able to defeat him, but as the city (And eventually other nearby cities were founded) grew the best of the challengers were able to carve out their own small domains. Over time, several of these lords changed, but the culture of sword dueling and that method of succession always remained the same. Over time, the number of Sword Lords stabilized at twelve, with each based in a different city, but Restov remained neutral and all the Sword Lords own a district in the city.
The Sword Lords have resisted against the Brevoy nobles as much as they are able, but have been kept under tight control. The Sword Lords will only duel each other when absolutely necessary, for the risks are so great and all their skills are so talented. Instead they maintain a shadow war against each other, each trying to outmaneuver each other and gain an advantage. Choral the Conqueror took advantage of this and turned them against each other to weaken them. They are starting to work together to try and overthrow the Brevoy nobility, but working against centuries of mistrust and intrigue, it is slow going. The fact that the Brevoy nobility keeps such close tabs on them does not make this any easier.