Esmerelda "Granny" Weatherwax is a character from the Discworld novels by Terry Pratchett. She's a good witch with a bad attitude who hails from the town of Bad Ass in the kingdom of Lancre. Granny is a respected leader amongst witches (Or would be, if witches actually cared about hierarchy even half as much as most wizards do). She is also among the most powerful magic users on the Discworld, and is not too modest to admit it. Granny uses little actual magic, however; she prefers to use her sheer old lady stubbornness, mixed with psychological warfare (which she calls headology), to get her way. She has even stooped to using the power of stories (as Discworld is the sort of place where stories happen, all the time), though she normally finds narrative causality (as Pratchett calls it) and its ability to strip people of their free will distasteful.
She is rather tall and thin, and is described as well-featured for her age. Granny considers this a disadvantage, as she would prefer to be a properly warty and ugly, and thus more intimidating, witch. She lives in an old, out-of-the-way, almost organic cottage, with beehives and goat pens in the back, and a small garden in the front full of exotic herbs and plants, some of which have been seen moving on a calm day.
In her long and illustrious career as a witch and general anti-hero, Granny has faced sexist wizards, extremely mean elves, extremely rude vampires, fairy tale endings that should not be, Nanny Ogg's singing voice, Magrat's ideas of what witchcraft should be like, and politics. She's a bit of a crank, as she often feels annoyed by the everyday idiocies of those around her. She does have her caring side, though, as much as she hates to admit it. She also used to have a bit of a relationship with Mustrum Ridcully, Archchancellor of Unseen University; but after the events of Lords and Ladies, he finally agreed with her to just be friends.
Granny is also a tad on the humorless side. In fact, Terry Pratchett says "She has no grasp of how or why jokes work -- she's one of those people who say 'And then what happened?' after you've told them the punchline." But that doesn't make her any less entertaining. It also doesn't stop her from trying (unsuccessfully) to tell the old joke about the alligator sandwich in Witches Abroad.