The City Watch is a law-enforcement institution charged with acting as the policemen of Absalom. They are informally known as "Green Cloaks" due to the green-colored cloaks their members wear as part of their uniform.
The City Watch of Absalom is a strong, formally-trained and well-equipped force of guardsmen under the direct authority of the Grand Council. Their salary is paid by the city as a whole and unlike many of the city's other districts they do not swear fealty to any lord other than the Grand Council.
The City Watch is supposed to double as a defense force in the event that the city is attacked, The City Watch are not really true soldiers, so they help protect the more inner parts of the city as the whole of the First Guard protects the outer parts and walls of Absalom.
The City Watch promotes by merit, one of the few institutions in Absalom not to recognize the status of birth. Its previous leader was Commander Jason Slante, a Tailor's son who rose through the ranks. Slante was dismissed by the Grand Council (where he is given a small seat amung the lower council members) and replaced as Commander of the City Watch by Brom, a lowborn sellsword who earned the rank after a few years of hard serivce.
The leader of the City Watch is referred to as "Lord Commander" when of noble birth, but simply as "Commander" when not. Jason Slante was merely a "Commander" due to his lack of noble birth. Following Lord Claark's arrest, Jason was named the new Lord of House Harren (A small new House) and elevated to the nobility by the Grand Council as a reward for his loyalty. After this point he was referred to as "Lord Commander" Brom was referred to simply as "Commander", as he was not of noble birth. Nonetheless, there is no functional difference, other than manner of address, if the leader is noble born or not.