Katrina, Cinderella's elder stepsister and biological daughter of Danton, occupies her stepfather's household alongside younger sister Jeanne and their mother, who remarried after the Duke departed abroad. Katrina actively participates in Cinderella’s mistreatment, enforcing her relegation to domestic servitude.

Raised as spoiled by her mother, Katrina exhibits consistent cruelty, condescension, and unfriendliness toward Cinderella, prioritizing luxury and fine things. She ensures Cinderella’s workload remains heavy, showing no sensitivity or reciprocation despite Cinderella’s persistent gentleness.

Socially ambitious, Katrina attends events like the town’s Flower Queen Contest while preventing Cinderella’s participation. She unknowingly interacts with Prince Charles disguised as a commoner, treating him dismissively and threatening to employ him at the castle once she marries 'the Prince'. Once, she exploits his disguise alongside her family, forcing him to perform Cinderella’s chores during her illness.

Katrina remains a primary source of Cinderella’s misery through unrelenting hostility. Her actions consistently reflect entitlement and cruelty, with no depicted character development or redemption altering her antagonistic role.