God moves in extremely mysterious, not to say, circuitous ways. God does not play dice with the universe; He plays an ineffable game of His own devising, which might be compared, from the perspective of any of the other players, ie., everybody, to being involved in an obscure and complex version of poker in a pitch-dark room, with blank cards, for infinite stakes, with a Dealer who won't tell you the rules, and who smiles all the time.
Terry PratchettI think when people mean that Discworld books have become darker they really mean the series is growing up. In 'The Colour of Magic' most of the city is set alight. It's a joke, in much the same way that the Earth is destroyed almost at the start of Douglas Adams's 'The Hitchhikers Guide to the Galaxy.'
Terry PratchettGranny Weatherwax was often angry. She considered it one of her strong points. Genuine anger was one of the world's greatest creative forces. But you had to learn how to control it. That didn't mean you let it trickle away. it meant you dammed it, carefully, let it develop a working head, let it drown whole valleys of the mind and then, just when the whole structure was about to collapse, opened a tiny pipeline at the base and let the iron-hard stream of wrath power the turbines of revenge.
Terry Pratchett