Hikari herself has no idea, but she's actually the last of her sub-species, a wind forbidden. Not many forbiddens at all remain and she's the first one sighted for Hundreds, maybe thousands of years.
She has no idea how to use her powers to the fullest but tries not to be a burden on those she cares about or those she travels with.
She's kind and gets shy toward Nick Strife and Reon Balisty, them being the first two who were kind to her besides her adoptive father.
She lost her memory in an accident, in which the lives of her true family were taken. She wandered astray in search of a "Familiar Face" when she met her two only friends who helps her to learn her powers.