Sergeant Angua of the Ankh Morpork City Watch. She's one of my favorite characters in Terry Pratchett's Discworld books. Delphine Angua von Überwald is the only werewolf in the Watch--that we know of.
Sergeant Detritus of the Ankh Morpork City Watch. Another one of my favorite Terry Pratchett characters. Detritus is a troll who's pretty green as we follow him through the book Men at Arms, but he's already a sergeant in Feet of Clay. One of the weapons he favors is a re-purposed siege crossbow named the "Piecemaker" that he's modified to shoot multiple bolts at once.
Commander Vimes: We first meet Sam Vimes as a miserable Night Watch captain in Guards! Guards!, when he's scrambling to keep his sanity as a lowly copper in a city that doesn't need him anymore. We meet Vimes when all he has are the scraps that remain after the guilds and nobles have divided up the wealth and decided what law and order will look like. As you'd expect, it's been beaten into a shape that best suits them.