Nakada(Nakata)4 Asumi voiced Cissnei in the Japanese version of Final Fantasy VII:Crisis Core. In an interview with Nomura Tetsuya (Creative Producer and Character Designer of Crisis Core) from the October 2007 issue of Dengeki Maoh, he commented that Nakada has been auditioning at Square-Enix since Kingdom Hearts, another one of Square-Enix's RPG titles, was in production. Nakada has left an impression on Nomura with her distinctive voice although he felt that they did not have any characters that her voice would suit at the time until Cissnei's appearance in Crisis Core. Nomura thinks that Nakada's voice could help Cissnei leave her mark in the player's heart even though Cissnei does not appear very often in the game.5
For more information on Nakada Asumi, you can visit her profile on her agency's website (Japanese).
English Voice Actress
Carrie Savage was casted as the voice actress for Cissnei for the English releases of Crisis Core. Savage is an experienced voice actress who has voiced many (dubbed) anime and video game characters prior to the role of Cissnei. Some of her notable roles include Mokona (Tsubasa Reservoir Chronicles / xxxHolic , 2005/2006), Yufa (Ragnarok: The Animation, 2004), Natalie Nanette (Radiata Stories, 2005), Xing Cai / Diao Chan (Dynasty Warriors 5, 2005) etc. just to name a few.
For more information on Carrie Savage, you can visit her profile on IMDB.
Personally, I prefer Nakada's portrayal of Cissnei over Savage's, even though both voice actresses played a teenage (Cissnei is 16 when she was first introduced in Crisis Core) to a young adult female character (she is around 20 near the end of the game) very well. In my opinion, Nakada's performance gave Cissnei a slight air of “coldness” and an air of “coolness” (aka badass-ness) while Savage's voice made Cissnei sounds more sweet and innocent. I think that “coldness” in Cissnei's voice suit her character quite well, since Cissnei is someone that grew up in an orphanage operated by Shinra, and was raised through strict education and training for the sole purpose of becoming a future Turks member. The “coolness” factor, I think, is something that comes with being a Turk. (See Rude when he's not being a comic relief along with Reno)
To be honest, I like Savage's voice for Cissnei as well, as I am more familiar with her voice as Cissnei's due to having played the game in English rather than in Japanese.