弱音ハク (Yowane Haku). Her character was the failed version to create 初音ミク (Hatsune Miku)'s voice, and her name means "uttering negative thoughts." I do know she is not technically an anime character, she is a Voyakiloid (Google is your best friend), but some consider VOCALOID and its sub-sectors to be anime characters, or at least resemble anime characters.