Appearance is most important when it comes to the witches. The witches' bodies are just plain revolting. They're deformed on the outside, which reflect their mean and messed-up insides: they're bald, have scabs on their heads, square feet, claws, and blue saliva. This is an image that, if nothing else, makes us remember that the witches are not human. They're monsters.
There sure is a lot of dialogue in The Witches, and for good reason. The narrator needs to learn from someone (Grandmamma) what the deal is with witches. The Grand High Witch needs to convey information to her gaggle of followers. Grandmamma and her grandson have some major planning to do. All of these things take some conversation time. Through the characters' speech, we're able to tell quite a bit about them.
Let's start with our narrator. He asks a lot of questions about witches, about mice, about fishing bait – there is nothing too small for a question. This might just tell us that we have a pesky narrator on our hands, but more likely, Roald Dahl is conveying his protagonist's curiosity. (For more on this, check out "Characters: The Narrator.")
The Grand High Witch also has some peculiarities to her speech. She rolls her "r"s and uses "v"s for "w"s. It all adds up to sound something like this:
"You brrrainless bogvumper! Are you not rrree-alising that if you are going rrround poisoning little children you vill be caught in five minutes flat? Never in my life am I hearing such a boshvolloping suggestion coming from a vitch!" (8.34)
You might notice that English isn't her first language. As strange of a creature as she is, her difficulty with the language just makes her sound even more distant from what we know as readers.
In case you haven't noticed, we keep calling our narrator "our narrator." This isn't because we want to remind you incessantly that he's the guy telling the story. It's because he doesn't have a name. In fact, Grandmamma doesn't really have a name either, just a title. Why on earth would the two main characters of a story (three, if you include The Grand High Witch) not have names? Well, it certainly makes them more adaptable. For example, instead of the narrator being one particular boy, we can almost think of him as an every-boy. That allows us to put ourselves in his shoes (and the fact that his grandma doesn't have a name adds to that possibility). It's a lot easier to imagine that we're a nameless boy than, for example, Percy Jackson.
What's more, our main characters seem to be the only ones without names. Almost all of the other characters in The Witches are identified by name. Of course there's Bruno Jenkins, our narrator's fellow boy-mouse. Then we have the vanished children from Grandmamma's stories, all with names (some first and last). Even some of the witches have names (Mildred, Millie, Beatrice). Even Timmy (4.61) and Ashton (6.10) – our narrator's schoolmates who are only mentioned in passing – get names. Even our narrator's mice, good old William and Mary, have names. All this makes it pretty clear that Roald Dahl didn't just forget to give our narrator and his grandma names. He did it for a reason.
Actions speak louder than words, or, in The Witches, at least equally as loud. We think of Grandmamma as a thick-skinned, tough nut of a woman, and our opinion is proven true by her actions. Think about how she goes ahead and moves to England with her grandson when his parents die. We know how much she loves Norway – she says it herself – yet she makes the immense sacrifice of leaving her homeland in order to take care of her grandson. This action shows her to be a loving, caring, and most importantly, selfless lady.
Our narrator takes quite a bit of action in the story, too. Most notably, he risks his own life in order to prevent the witches of England from killing all of the country's children. Not many of us have been put in this kind of a situation, but you can imagine it would be tough. Still, our narrator does it with gusto, showing himself to be courageous and, like his grandma, unselfish.
But if you think that actions only define the good characters, think again. Aside from their ugly, monstrous bodies, how do we know the witches are evil? Because they turn kids into mice, that's how. The witches are mean to kids, which proves that they're bad to the bone.