Rosa

Rosa Diaz is a smart, tough and mysterious (she assumes multiple identities for different people). Although Diaz is a loyal and effective member of the squad, her anger management issues and lack of empathy terrify most of her coworkers. She is highly secretive about her personal life, and refuses to let any of her coworkers visit her home, despite living very close to the precinct. She is shown to own many weapons and believes that every woman should own an axe and it is suggested several times that axes are her one of her favorite weapons. Rosa also owns multiple swords. She always carries a big knife hidden on her persons. Rosa is the scariest detective in the precinct, but is not a bad person, proven by her fierce commitment to being a detective, and how she proves useful when paired with other detectives. On the other hand, they often have to put up with her savagely blunt nature whenever she's around.

Rosa comes from a religious/traditional family in Bensonhurst. She has two sisters and a niece named Diana, who she spent Thanksgivings with before the squad started celebrating together. Her father is a teacher.

Rosa previously attended a parochial school where she was a model student and had a favorite teacher, Sister Bernadette, but eventually dropped out.

Rosa is Latina with a light-brown complexion. She has curly, dark hair that is never seen in an updo, and in season seven, her hair is brown with highlights in it. She has dark, brown eyes and a thin cut in her right eyebrow (Beatriz tripped on a Lego brick when she was 10).

She often wears a black leather jacket (having a "nice one" that doesn't have any bloodstains on it) and black jeans or 'badass' clothes. She often has an offensive stance, with her arms crossed and a scowl on her face.