Haru joins the Thieves as the only senior student in the group, she's the daughter of the president of a country-spanned food manufacturer. She's a very soft-spoken person, though elegant in how she converses due to her upbringing in an elite family. She feels chained down by her father, and despises having everything in her life be chosen for her.
She has difficulty in telling people who sees her as a "friend" and those who merely wants to use her for her family's status. She calls Makoto "Mako-chan" as she sees her as the first, true friend she's ever had, much to Makoto's appreciation. She initially teams up with Morgana, who has left the Thieves, to help her pursue her father's treasure inside his Palace. She refuses to work with the Thieves, due to their internal fighting, and relies instead on Morgana to help her.
Once she encounters the Shadow of her fiance inside the Palace, and he reveals his intentions to use her as a sexual plaything, she awakens to her Persona "Mylady" in outrage. She officially joins the Thieves soon after, with the handler name "Noir", to help them change her father's mind about the marriage, as well as putting a lid on his ruthlessness business behaviour.