Well...There isn't really much to say about Hikari. She's an average ninja, with average brains, and average...everything.
Despite her name, and how she acts, she can only control the darkness element. (Hikari means light)
She is normally, a kind and cheerful person. She doesn't like hurting others, and doesn't wish bad things on people.
Despite her dislike for war, she does like a good brawl every once in a while, as long as the outcome isn't severe.
There's a weird occurance when she is fighting however, when she gets too involved in the fight, a darkness takes over and her personality goes out of wack.
All she wants in life is to have a roof over her head, some food on the table, and perhaps a respectable rank. With no high ambitions, she's pretty easy going.