Shizuku Ishiki

Kasumi's twin sister, identical to her if not only for their hairstyle, the fact that she didn't wear glasses, and her upbeat and cheerful personality. Infected with Medusa, despite being left out of those chosen to be cured, among who there was her own sister, she still greatly supported her and insisted for her to take the chance to be saved from Medusa.

(Source: Wikipedia)