Kei (ケイ Kei) is a member of the Resistance, which Mr. Nezu and Ryu, their leaders, are part of. She is voiced by Mami Koyama in Japanese, Lara Cody in the 1989 Streamline English dub, and Wendee Lee in the 2001 Pioneer English dub.
As a member of the Resistance, Kei helped in the escape of Takashi. She was arrested shortly after that until Kaneda, who became infatuated with her and freed her with a manipulation of his. She is grateful for what he did, but is also aware of his wish to connect with her.
After that she leaves him and continued with her activities in the Resistance. In time, however, she is aware of his relationship with Tetsuo and makes sure he becomes a member of the Resistance.
Additionally she develops a romantic relationship with Kaneda to whom she becomes close. Later it turns out she also has psychic powers, which the psychic trio intend to use for their goals.
Through her the trio fights against Tetsuo with no success, when he is about to discover Akira. When the Resistance is destroyed, she becomes even closer to Kaneda and his gang and becomes really fond of them. She witnesses the return of Akira and the corrpesponding destruction of Neo Tokyo and ensures through her appearance that Kaneda survives it.
After that she, Kaneda and his friend go away from there.