A young woman whom Kaneda meets on his quest to find Tetsuo. She is a member of an anti-government organization that Ryu and Nezu are also involved in.

What is not mentioned in the anime movie is that Ryu is actually her older brother.
She is seemingly better looking in the manga, and appears to be somewhat older than Shotaro Kaneda, just as he appears younger in the manga.

Kei's role in the Resistance is important because she is completely loyal to its cause and to Ryu. Her character is far more developed in the manga, where she plays more than a "hard-to-get" love interest for Shotaro Kaneda. She is strong willed and is the one to discover that Lady Miyako is an Esper too. Miyako helps Kei channel her thoughts and discovers she is a conduit for the Espers' telepathy. Kiyoko does this in the movie and Kei communicates with Kaneda and Tetsuo. She works closely with Chiyoko, a physically strong and resilient resistance fighter and they look out for each other.