[[quoteright:309:http://static.tvtropes.org/pmwiki/pub/images/ibbotsonwhichwitch_1698.jpg]]

Arriman Canker, otherwise known as Arriman the Awful, Loather of Light and Wizard of the North, is getting worried. He's starting to get up there in years, and has no black wizard to pass his legacy on to. A no-nonsense fortune teller insists that one with even more potential than Arriman is on the way, but there's no sign of him ever making an appearance. Thus, though he's not too keen on the idea, Arriman decides to marry a black witch so that he can produce an heir the old-fashioned way.

Of the witches in the area, the pickings are slim. His options are Mabel Wrack (the daughter of a mermaid-turned-human), twins Nancy and Nora Shouter, the uncouth Ethel Feedbag, the ever-befuddled Mother Bloodwart, sinister Madame Olympia, and sweet Belladonna. To choose, Arriman proposes a contest for them: they must all perform acts of black magic for him, and whoever does the most evil thing will be his wife.

Meanwhile, for Belladonna, it's LoveAtFirstSight when she sees Arriman. She's determined to win at all costs, but there's a minor setback: she's not a dark witch at all. In fact, she's a white witch, who can only perform good magic. But luck seems on her side when she meets an orphan boy named Terrance Mugg, whose pet worm, Rover, appears to be Belladonna's familiar, capable of giving her dark magic. With Terrance and Rover on her side, Belladonna is certain to win. But will she come out on top, when one of the group resorts to underhanded methods to win?

Written by Eva Ibbotson, ''Which Witch?'' tells a story of magic and good and evil and love... all in the most hilarious way possible.

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!!Trope examples:

* AlliterativeFamily: Nancy and Nora.
* AllOfTheOtherReindeer: Belladonna is hated by pretty much every other witch in the coven, because she's a good witch. The only one who's at all kind to her is Mother Bloodwart, and even she isn't too comfortable talking about Belladonna's... differences.
* BottomlessPit: A non-video-game example, created for one of the challenges.
* BeAsUnhelpfulAsPossible: Esmeralda the gypsy assures Arriman that a new dark wizard ''is'' coming, but is very rude about the whole thing and of course can't tell when or where the successor will come.
* BerserkButton: Neither of the twins take it well when Ethel suggests that their chicken laid an ordinary egg. Also, later in the book, Arriman nearly throws a fit when he learns that [[spoiler:Belladonna intended to perform necromancy for him, which was the one thing he couldn't manage and wasn't happy about it.]]
* BeautyEqualsGoodness: Played with. Belladonna, the only white witch, is beautiful while the dark witches are all hideous. But Arriman, who is the darkest wizard of England, is very handsome, and Belladonna ''aspires'' to be evil.
* BlackWidow: Madame Olympia, who went through quite a few husbands.
* CuteWitch: Belladonna.
* DarkIsNotEvil: Arriman the Awful, Loather of Light and Wizard of the North, is really a nice guy despite the whole black-magic thing.
* EverythingsSquishierWithCephalopods: Mabel's familiar, Doris, is an octopus
* EvilIsPetty: The dark witches tend to do nasty things to people just because they ''can'', or because they hate the sight of happiness. In her EstablishingCharacterMoment, Mabel magics a beach full of stinging jellyfish, just out of annoyance at the sight of children happily swimming there. A more malicious example happens at the end, where [[spoiler:Madame Olympia steals Rover to ensure her victory, then intends to burn the poor thing just because she's angry she lost. She also makes it clear that she intends to show up later to poison Belladonna, for beating her in the contest.]]
** We find out that Matron hates Terrance and goes out of her way to be horrible to him (up to and including [[spoiler:trying to kill his pet worm]]) is because [[spoiler:when he was a baby, he once bit her finger.]]
* {{Familiar}}: Every witch save Belladonna has one. Unusually, none of the witches has a cat familiar -- instead we see an octopus, a pig, two chickens, a box of flies, a sheep, an aardvark, and a worm, [[spoiler:though it turns out that last one ''isn't'']].
* FriendToAllLivingThings: Belladonna, who is beloved by pretty much every animal she comes across.
* GentleGiant: Lester the ogre.
* LoopholeAbuse: Of a sort. Mabel sets about summoning the Kraken, and she ''does''. [[spoiler:It's the baby Kraken, though]]. Arriman is so annoyed that he wants to give her no points at all, but relents when the other judges remind him that she technically ''did'' do what she said she would.
* LoveAtFirstSight: Belladonna falls for Arriman the instant she lays eyes on him (as do most of the other witches). [[spoiler:It works the other way too, with Arriman falling in love with Belladonna the instant he looks at her and wanting to marry her "tomorrow at the latest".]] Also seen with the genie judge and one of the princesses turned into a black swan ([[ItMakesSenseInContext really a penguin]]).
* MagicFeather: Terrence thinks his pet worm is magical; it turns out that [[spoiler: it's a normal worm, the magic came from Terrence all along]].
* MakeupIsEvil: Madame Olympia owns a beauty parlor. She enchants her products so that they really do make the customers look incredibly beautiful at first, but then they wear off and leave the people uglier than before, forcing them to keep coming back again and again.
* MamaBear: The thing that pushes Belladonna to do the first remotely black thing in her life is watching Matron (who [[KickTheDog had tried to squish Rover, earlier]]) yell at Terrance and try to drag him away. It angers Belladonna so much that she halts Matron by turning her partially into a tree.
* MinionWithAnFInEvil: Before becoming Arriman's assistant, Mr. Leadbetter thought he was a demon of some kind, because he had a small devil-like tail. Since he figured this was the case, he tried to rob banks for some time. It didn't work out.
* MyMasterRightOrWrong: Arriman's servants agree to most of his ideas, even if they don't think much of them. Subverted near the end though, [[spoiler:when they conspire to rig his tournament so that Belladonna will win, because they think she's the best and most deserving candidate.]]
* NamesToRunAwayFromReallyFast: Arriman is named for Ahriman, a GodOfEvil in Persian mythology. This is explicitly stated, although he did change the spelling.
* NiceGuy: Terrance. [[spoiler:Surprising, considering that he's destined to be come an evil darker wizard than Arriman...]]
* PairTheSpares: Rather amusingly done between [[spoiler:[[TheBluebeard Sir Simon]] and [[BlackWidow Madame Olympia]]. To keep them both from causing problems in Arriman and Belladonna's marriage, their wedding drinks are spiked with love potion so they fall for each other. There's some debate as to which one would kill off the other.]]
* SophisticatedAsHell: The Wizard Watcher tends to talk like this.
-->'''Middle Head:''' He cometh not from the north.
-->'''Left Head:''' He cometh not from the west, neither.
-->'''Right Head:''' Nor from the east doesn't he cometh. And our feet are ''freezing''.
** This is followed up by them relaying those messages to Arriman, along with "We think you've been taken for a ride."
* SickeninglySweethearts: [[spoiler:When Arriman finally meets Belladonna, his new bride, they instantly start calling each other pet names and wanting to be wed the next day at the latest.]] Arriman's assistant is not amused.
* SingleMindedTwins: Nancy and Nora are identical, have exactly the same animals as familiars, and constantly bicker about the same subject matter.
* TallDarkAndSnarky: Arriman the Awful. Not quite as snarky as other examples, but he has his moments.
* TheBluebeard: Parodied with Sir Simon Montpelier, whose murdering of his seven wives ends up being PlayedForLaughs. [[spoiler:When he comes back to life, he does absolutely nothing but talk about how he killed the wives, until everyone is desperate to be rid of him.]]
* WorkingClassPeopleAreMorons: Ethel Feedbag.