Sophie Lydon is the secondary antagonist of the ninth book in the Cherub series, Dark Sun. She is the daughter of the Dark Sun member Kurt Lydon and a "grade one pain in the butthole" and "evil b**ch" according to her brother George.
Sophie is the sister of George Lydon, who Cherub agent Greg "Rat" Rathbone is apparently attracted to. George, his friend Zhang, and Rat attempt to prank Sophie by throwing coleslaw at her, but she moves and the coleslaw hits Thomas Moran instead, causing Thomas and Johno to chase them. Sophie later appears when Rat and fellow agent Andy Lagan have a sleepover at the Lydon house with George and Zhang. George confronts Sophie for giving away half his PSP games (then breaks into her room and taunts her), but she stops him and goes to the cinema with her boyfriend Daniel. She arrives back later and is encountered by Rat and Andy when she's vandalising the carpet to get George into trouble. Rat hits on her in order to get past her and into Kurt's office, but she freaks out and tries to attack him, resulting in Andy sedating her. The next morning, she tries to blame the carpet vandalism on George, but Rat says he saw her vandalising the carpet and that she attacked him. She lies, trying to claim that Rat molested her, but no-one believes her lies and she is forced to clean up.