Keiko Kitagawa is a Japanese actress and former model. She was an exclusive model for the Japanese Seventeen magazine from late 2003 to mid-2006, and quit modeling when she left the magazine. Her first acting role was Sailor Mars in the Sailor Moon live action show Pretty Guardian Sailor Moon (2003-2004), and after her role in the film Mamiya Kyōdai, she left modeling to concentrate on acting. She has appeared in several films, including The Fast and the Furious: Tokyo Drift (2006) and Handsome Suit (2008), and has played leading roles in the TV Dramas Mop Girl (2007), Homeroom on the Beachside (2008), Buzzer Beat (2009), Lady Saigo no Hanzai Profile (2011), and Akumu-chan (2012).

Rei Hino , better known as Sailor Mars , is a fictional character in the Sailor Moon manga series written and illustrated by Naoko Takeuchi. In the series, Rei is her sailor form's alternative human identity as part of the Sailor Guardians, female supernatural fighters who protect the Solar System from evil.