Ann is a very compassionate, and sweet person, noted by both Morgana and Sojiro. Most of her time spent at Shujin has been that of loneliness, as a half-American she's branded a 'foreigner' despite her birthplace being Japan. This has result in her having to endure untold levels of nasty rumours, and not having many friends except for Shiho Suzui. She's a good judge of character, partially shown in the people she befriends. While she seems distant and quiet at first, partially because of the rumors but also because she's being used by the gym teacher Kamoshida. This changes once she opens up to the protagonist, and decides to see him for who he really is. Even more so when she joins the Thieves themselve, she can be laidback, carefree and genuinely happy. She's also not uncomfortable around guys, to a point where she doesn't mind sleeping in the same room as them or resting her head on Ryuji's back.
Her good sense is also what allows her to forgive Makoto, after she decides to hear her side of the story regarding the whole Kamoshida business. The abuse she's had to suffer from both the rumors, and Kamoshida, is part of what makes her the moral center of the Thieves. Thanks her friend Shiho, who decided to get to know the real Ann, Takamaki decides to show the same courtesy towards others. She questions on whether "changing someone's heart" is the right thing to do, while still ascertaining that the number one priority is to use their abilities to help people in trouble.
Dressed in a red cat suit, inside the Palace Ann dubs the call name 'Panther'. When Shadow Kamoshida captures her he reveals that he sexually assaulted Shiho, but also that she's to blame for it for rejecting his advances. Her pent up frustration and anger triggers her Awakening. Her Persona Carmen is based on the fictive gypsy created by author Prosper Mérimée. The character's rebellious attitude and refusal to submit to the will of another reflects Ann's disposition towards Kamoshida and how she doesn't care about what others think of her.
As an active member of the Thieves, Ann is very energetic and agrees to continue doing what they did for her to others in trouble. She believes that if she refuses to act she'll go back to how she was before, and more people will end up like her.