Haruna is not a main character by any standards, though she holds her own very well as a supporting character. She is mainly a part of the Library Exploration Club along with her friends, Nodoka and Yue. While Haruna does think that Negi is cute, she prefers to use her energy helping Nodoka to score points with Negi, egging her to go farther with him and sometimes hitting her when she screws up. Haruna may make Nodoka go all the way with Negi if given the chance.
Unlike the other Library Explorers, Haruna is into manga which she not only reads but draws as well. One of her works includes Mahou Shoujo Bibulion which is considerably popular at Mahora. Haruna also goes under the pen name "Paru". Also unlike the other Library Explorers, Haruna is still in the dark about Negi's magic powers. This is because Haruna's a gossip, always seeking to find and tell about the latest events. Especially when it deals with LOVE.
She is a talented artist who draws a manga series, and a frequent companion of Yue and Nodoka. After finding out about the existence of magic, she is initially hurt that she wasn't told, though they explain it was because of her gossiping. Haruna's mouth also extends to openly suggesting various romantic entanglements in order to cause parties embarrassment. Much to her classmate's chagrin, she is unusually perceptive about such matters, for example quickly identifying Natsumi's developing feelings for Kotaro. She forms a pactio with Negi, "Imperium Graphices" which takes the form of a sketchbook able to bring any drawing to life for a short time. She becomes very adept in using her artifact, able to create complex drawing in seconds that can attack or defend. She can also draw copies of herself, allowing her to draw at a much faster pace.