Justine is a key supporting character in Persona 5, serving as one of the twin wardens of the Velvet Room alongside her sister, Caroline. She appears as a young girl dressed in a blue prison warden uniform and helps manage the protagonist's rehabilitation under Igor's guidance. Justine is calm and polite, contrasting with her sister's more abrasive demeanor. Together, they represent two halves of a whole, playing a crucial role in the protagonist's journey and the Velvet Room’s mysteries.