Riku has a hesitant, soft voice, however lots of people mistake her as a boy instead of a girl. (I'd perfer her voice to be similar to Hideyoshi from Baka & Test) Her personality is, of course, hesitant and shy, but she won't put up with anyone's crap. However she does end up doing things she doesnt want to do, due to her kindness & the ability to be unable to say "no".