Haruna Kisaragi

Yui's best friend. She has a polite, calm, and caring personality. Her intelligence and innate ability with computers makes her a perfect candidate for Corrector, as expected by Dr. Inukai. From the beginning she was supposed to be a Corrector, but I.R. confused her with Yui, thanks to Grosser's intervention.

When Dr. Inukai was passing Corrector tasks and abilities to her, she got manipulated by Grosser, who turned her into Dark Angel Haruna, but she was eventually saved by Yui. In the 2nd season, she again returns as a Corrector to assist Yui, first when Yui got petrified by infected insects, and later, when she helps Yui until the end of the 2nd season. Curiously, she can use Element Suits more effectively than Yui.

(Source: Wesker_CDA)