Kei Mizusawa is a Japanese voice actress born on September 14, 1975, in Nagasaki Prefecture. She is affiliated with the talent agency Yellow Tail. A graduate of the Visual Techno Academia arts and media training institution, she began her career in the early 2000s. Earlier in her career, she was known by the stage name Madoka Horiike, and she has also worked under other names, including Rino Kawashima, particularly for her extensive work in visual novels.

Her career is marked by a high volume of roles across anime, video games, and drama CDs, with a significant presence in the visual novel genre. In anime, Mizusawa is known for several prominent roles. She voiced the character Kei Sakurai in the series Dies irae: To the Ring Reincarnation and Yoko Kasaya in Saiminjyutsu 2nd. Her other notable anime roles include Machi Yatsuzuka in Mashiroiro Symphony - The color of lovers, Shizuka Satsuki in Kurutta Kyōtō Danzai no Gakuen, Tokisaka Yukari in the Girl in the Shell series, Sae in Tony's Heroine Series: Kanojo wa Hanayome Kōhosei? Cinderella Collection, and Keiko Mitarai in Fella Pure: Mitarashi-san Chi no Jijō The Animation.

Beyond these specific credits, Mizusawa has built a substantial career with many recurring and leading roles. She is widely recognized for her portrayal of Shuyu in the Koihime†Musou franchise. She also played significant parts such as Asako Kusakabe in the Grisaia series, Margit Eberbach in Majikoi! O: Samurai Girls, Clarissa Harfouch in IS: Infinite Stratos, Airi Hasekura in Lost Future, and Sillia in Walkure Romanze. Her work is extensive in the gaming world, lending her voice to characters like Kohaku in Aoi Shiro, Yuzuriha Yatsushiro in the FLOWERS series, Haru Usami in The Devil on G-String, and Yuki Minakami in Wonderful Everyday Down the Rabbit-Hole.

Throughout her career, Mizusawa has demonstrated versatility, often portraying a range of character types from heroines to supporting roles. She has also contributed to drama CDs, dubbed foreign films, and hosted radio programs. In 2013, she released a music album titled Magic hour, showcasing her talents as a singer. Her hobbies include watching theater and illustration, and she has a background in the martial art of kendo.