She has shoulder-length brown hair, is (supposedly) attractive, and hangs around Daichi at every possible opportunity. She fantasizes quite a bit, and has an extremely high opinion of herself (she's stuck-up). She has a unique bit of theme music that is almost always played whenever she confronts Himeko.
Hikaru's family is made up of her father (who is a doctor), her mother (who is a nurse), and herself. But they also hire a helper to take care of their house.
Also Hikaru is the only person besides Daichi to suspect that Hime-chan has more powers than an normal girl.