A group from Terry Pratchett
's famous Discworld
The Ankh-Morpork City Watch was originally divided into four distinct sects: The Day Watch, the Night Watch, the Palace Guard, and the Cable Street Peculiars (a group of "secret" police), who patroled the byways of the city, either solving trouble or avoiding it. But eventually, the aggressively libertarian and liberally aggressive nature of Ankh-Morpork's populace (helped in no small part by a temporally-displaced Sam Vimes) led to the dissolution of the Peculiars.
Soon, the reign of the Ankh-Morpork Kings gave way to the reign of the Patricians. As time went on, the Day Watch and Palace Guard were reduced to a pack of poseurs who tended to arrest the first suspect that was convenient (the philosophy of former Day Watch Commander "Mayonnaise" Quirk was "It doesn't matter if you're right or wrong, so long as you're definite."), while the Night Watch degraded to a pack of laughable unemployables.
But after a series of uncharacteristically heroic antics (inspired in part by new recruit Carrot Ironfoundersson), the Night Watch gained prominence, and eventually took over the jurisdiction of the Day Watch.
Today, the City Watch is a disciplined, hard-working (for the most part, at least) team of crime-fighters. The City Watch also has an interesting affirmative action policy: they'll take anyone except vampires.
The core members of the City Watch are:
Commander Samuel Vimes: Vimes was once a drunken, authority-hating cynic with no direction in his life, placed in charge of a pathetic shadow of the Night Watch. Since his marriage to Sybil Ramkin, he has become a teetotaling, authority-hating cynic with a dedication to fighting crime (including crimes against humanity such as war and diplomacy), leading a far more competent City Watch. Officially Duke of Ankh-Morpork, much to his chagrin. His movement into the upper class has, if anything, exacerbated his hatred of social injustice.
Sergeant Fred Colon: One of those fat policemen who doesn't do much except yell at people and wait for retirement; he's described as the sort of person who seems to naturally gravitate toward the rank of sergeant. While he has made some accomplisments in the past, he currently seems satisfied with his job in the Traffic Department. He is married, but how he and Mrs. Colon (who work radically different hours) managed to start and raise a family is beyond me. He once thought about taking up farming, but after a traumatic experience with some escaped livestock in Feet of Clay, he has decided to remain in the Watch. He is usually seen hanging out with:
Corporal Cecil Wormsborough St. John Nobbs (Nobby to most people): A small, wiry, unpreposessing smart-aleck with a "colorful" sense of humor, a collection of interesting boils, and an uncanny resemblance to a shaved chimpanzee. Once a petty crook, he has reformed (for the most part) in recent years. He is rumored to be the last surviving heir of the Earl of Ankh, but being the sort who lives in fear of responsibility (and of Commander Vimes's opinion of nobility), he prefers not to talk about it. He follows the old military adage "Never volunteer" to a T. Nobby briefly picked up a habit of crossdressing after the events of Jingo, and during the events of Thud!, he had the good fortune to date a hot exotic dancer named Tawneee by being the first guy who didn't think of her as unapproachably beautiful.
Captain Carrot Ironfoundersson: Physically, he's a 6'6" human with red hair and rugged good looks; mentally, he's mostly dwarf. Raised in the Ramtops by a family of dwarfs, Carrot left to join the Ankh-Morpork City Watch so he could make a man out of himself. He wound up saving the city several times and helping to make the Watch the well-oiled machine it is today. Carrot is rumored to be the lost heir to the long-abandoned throne of Ankh-Morpork, but he steadfastly denies it, even if he does have a fancy sword, a crown-shaped birthmark, and a talent for getting people to listen to him. Apparently, he thinks Lord Vetinari does a good enough job.
Sergeant Detritus: A troll. He's big, he's made out of rock, and he's not much of a detective (he hasn't got the hang of questioning suspects, outside of saying "It was you what done it, now own up!" over and over). Even other trolls consider him stupid. However, his silicon-based troll brain works much better in cold weather. In sub-zero temperatures, he can be a veritable genius. He's mainly the muscle of the Watch, though. He has a custom-made crossbow that was originally a siege weapon. For warm days, or times which require him to do some deep thinking, he has a fan in his helmet (build by his old partner from his first apperance in Men at Arms) to keep his brain cool.
Sergeant Delphine Angua von Uberwald: The first woman to join the City Watch, and also the first werewolf. A stunningly beautiful woman with blond hair in her human form, she feels rather awkward about her werewolf nature, and prefers to keep it a secret. Angua left her home in Uberwald to get away from her family, whom she rightly regards as a bunch of savages and egomaniacs. She and Carrot have an "understanding".
Corporal Cheery Littlebottom: A former alchemist, and the forensics officer of the Watch. One of the first openly female dwarfs on the Discworld. All dwarfs on the Disc, regardless of gender, have extensive facial hair, and most of them prefer to think of gender as a private matter. For that reason, Cheri (as she likes it to be spelled) has come under a lot of discrimination.
Other important or interesting members include Constable Visit-The-Infidel-With-Explanatory-Pamphlets (a well-meaning but annoying Omnian with a bad habit of proselytizing, affectionately refered to as "Washpot"), Constable Dorfl (a free-willed golem best described as a ceramic Robocop with philosophical tendencies; being effectively lightning-proof, he's also the safest agnostic on the Disc), The Librarian of Unseen University (he was made a Special Constable of the City Watch in "Guards! Guards!"), and Salacia von Humpeding (the Watch's first vampire officer, introduced in ''Thud!''; you can call her "Sally").