In 1774, while the Carrolls were visiting the de la Serres to voice the worrying of the foreign rites concerning the reformist faction of the French Rite, May taunted Élise de la Serre, because as a ten year-old, May had been told of her Templar destiny while the six year-old Élise had not.
In 1788, Élise came to London, asking the Carrolls for help in order to investigate the assassination attempt on her mother a decade before. Oblivious to the fact that it was the Carrolls who had hired Bernard Ruddock in order to kill Julie, who was a moderate reformist but had the ears of her husband, Élise accepted their bargain: they would search for Ruddock, while she tried to obtain the letters of Haytham Kenway from his sister, Jennifer Scott.
Élise obtained the letters and, after reading them, decided that the Assassins and Templars needed to work together. She found Ruddock by herself, allowing him to flee because she thought that the Carrolls were trying to silence him. Soon afterwards, Mr. Carroll obtained a pack of decoy letters, which he passed onto May, who swiftly burned them. Mr. Carroll said that even though Grand Master Kenway was a great Templar, his ideas about the Assassins were blasphemous.
Upon hearing Élise defending Kenway's view, he said that she was too dangerous to be left alive, and the Carrolls, along with their men, readied themselves to kill her. Élise was given a chance to duel May. Making the first move, she stabbed May through the back of the neck, and used the Carrolls' shock to flee, but also attracted the hatred of the Carrolls on herself, and by extension, the mistrust of the British Rite. Various individuals would be hired to assassinate Élise, her guardian Frederick Weatherall and even her serving girl Hélène.
Personality and traits
May was an extremely nasty and unpleasant person, which likely stemmed from her parents. Even at the age of ten she was conceited, arrogant, cruel and snobbish. Despite being fellow soon-to-be Templars, she constantly belittled and insulted Elise de la Serre, giving her the name 'Smellbag'. This continued on into her adulthood, where she plainly told Elise that the dress she had lent her was considered out of fashion and no London woman would wear it anymore. This arrogance cost May her life, however; when she turned her back on Elise while taunting her, Elise took advantage of this to run her through from behind.