Karmi is introverted, studious, and takes great pride in attending college at a young age. However, she keeps to herself most of the time. Karmi comes across as aloof; she feels comfortable in her field of research, so Karmi is disinterested in social interaction. She is unfriendly with Hiro since the boy is sharing the spotlight of being a young genius like her, and at one point accused him of being ignorant of science when he didn't grasp what her research was about. Despite her intelligence, Karmi can be oblivious to the truth, even when the evidence contradicts it. This included her being unable to recognize Hiro in superhero form and when she misinterpreted Hiro defending her as him having feelings for her, which Karmi ironically returned.
Karmi has an obsessive relationship with her virus samples, seeing them as the only true companions she has. Karmi went as far as to interact with them and giving them names, and reacting in horror when one was destroyed.
Whenever she is around Professor Granville, she acts optimistic and engaged, and friendly with Hiro.
Karmi is an adolescent girl with olive tan skin, long brown hair, and is a little taller than Hiro, although the two are close in age. She ties her hair back in a ponytail, and wears a cream-colored turtleneck, black pants under an orange skirt, and black shoes. For accessories, Karmi wears red earrings and two red and yellow bracelets on her left wrist.
In "Issue 188", Professor Granville introduces Hiro to Karmi as a means of improving Karmi's social skills. At first, Karmi treats Hiro with disdain and annoyance. However, Hiro discovers that Karmi has a crush on his superhero identity when he sees her drawing him in her textbook. During the fight between Big Hero 6 and High Voltage, Karmi witnesses the event among the crowd. She is nearly crushed by a falling street lamp until Hiro (in his alter ego) saves her. While recovering, Karmi giddily takes a picture of Hiro.
Fortunately, Karmi does not realize Hiro's secret and fails to see the resemblance between her crush and Hiro. After meeting with Granville, Hiro actually thanks her for helping him how to socialize. Karmi is shocked as Hiro did not rat her out on her behavior and assumes Hiro is crushing on her, which Hiro denies.