Nanami Arihara is a main character in the visual novel 'Riddle Joker'. She is a student at the special academy that trains individuals with unique abilities known as Astrals. Nanami is known for her upbeat personality and her close relationship with her younger sister. She possesses the Astral ability to manipulate the flow of time within a limited scope. Her cheerful disposition and determination make her a central figure in the story as she navigates the complexities of her powers and personal relationships, contributing significantly to the series' unfolding narrative.