Margaret Mearle is a supporting charcter in Heartless and is primarily based off of the Duchess from Alice in Wonderland.
She is described as unattractive, with eyes spaced too close together and the bad habit of resting her large chin on people's shoulders.
She was first introduced during the King’s black and white ball at the beginning of the book. As Cath wandered the dance floor worrying about her noticeable red dress, Margaret approached her, much to her dismay. According to Cath, she and Margaret had been bosom friends since they were toddlers, but they had never much liked each other, given how Margaret made it clear how much better she was than everyone else, and pointed out Cath’s faults every chance she got. Around people she wanted to please, she acted like a defined, polite lady, but behind their backs, she was actually a snobbish, vain and rude person.
Margaret multiple times throughout the book mentioned some of her morals, which were pointless and ridiculous in themselves, but made most people act quite inspired (excluding Cath).
After their conversation was interrupted by Jack the Knave and the King’s entrance, Cath slipped away, leaving Margaret by herself. Soon though, after the Joker’s performance and just before the King’s proposal to Cath, she was attacked by Cheshire as a distraction and almost killed by the Jabberwock a few moments later. She was only saved by the Duke of Tuskany, who adored her, though she never thanked him for it or showed him any appreciation. She later called Chesire a nuisance to society during the garden party, almost ignoring Cath’s concerns about the Jabberwock.
Despite Cath’s attempts to warm her up to the Duke during said garden party, knowing that he fancied her, she wanted nothing to do with him, seeing him as an arrogant elitist. She afterwards played croquet with Cath and the King, but halfway through threw a tantrum and smashed her club because her flamingo wasn’t winning the game for her.
After Jest died, she showed no signs of grief or pity, and acted completely happy and at peace when she came to Cath and the King to confirm her marriage with the Duke. Then, it seemed that she was fully in love with the Duke, even gasping and shaming the King when he reminded her that he was a pig. Cath, impatient and infuriated by the death of Jest, stood from her seat and told the jury and the Duke that Margaret had always considered him to be a dull rude character, and that she was marrying him for money. Margaret, stunned for a moment, proceeded to tell her that the moral of that was to never judge a book by its cover. Throwing her hands into the air, Cath huffed and granted their marriage as Queen.