A latened Psychic. Yay.
She's a very lighthearted girl. She's willing to risk anything and/or everything for her friends. When she's on a case, she won't stop until the case is solved, which shows she's determined and focused. She doesn't like to give up. She's also a very loyal girl, she keeps every promise she makes, never breaks a promise unless it's absolutely mandatory, and sometimes not even then.
Nothing much...
She was just a regular girl until she entered an old schoolhouse next to her school that is claimed to be haunted. Apparently Naru was investigating, because Mai accidentally toppled a bookshelf on top of his assistant Lin and the very expensive camera (which was covered by insurance.) She worked for Naru ever since to make up for the broken camera and assistant. Now she works for him (would you call it full time, or still part time coz she's still in school?), but more because of the job and experience, not the camera and now better than before Lin.