Kei Tomoe is a Japanese talent, idol, actress, and voice actress born in Tokyo on January 5, 1996. Her blood type is O. She is affiliated with the agency Horipro International. Tomoe is a member of the girls' drama unit Girl ACTRY and was also a member of AOP, an anime support project. Her known interests include video games, watching anime, and fashion, and she has training in classical ballet, which she practiced for eight years.

Tomoe is best known for her leading role as Komugi Yoshida in the 2016 anime series Nurse Witch Komugi R. In this series, she portrayed a cheerful and aspiring idol who gains magical powers. As part of this role, she performed the series opening theme song Ready Go!! as a member of the unit Magical R, alongside her co-stars Erii Yamazaki and Makoto Koichi.

Beyond this primary role, her other voice acting credits include performances as a high school girl in the 2011 film Onigamiden (also known as Legend of the Millennium Dragon). In 2016, she provided additional voices for the acclaimed film In This Corner of the World and appeared in the series Time Travel Girl: Mari, Waka and 8 Scientists, where she voiced several minor roles including a female character, a smartphone, and a man. In 2020, she had a role as Woman A in the series Tsugumomo. She also appeared in the television program Hi☆Channel as herself. Her early career included the role of Makino Erika in the 2012 video 2 Channel no Noroi - VOL. 7 and a part in the 2011 production Chikyû bôei Girls P9.