Rei Ayanami is the First Child, and the pilot of Evangelion Unit 00. She is shown to be socially withdrawn and hardly interacts with anyone. Rei's cool, silent and emotionally-stunted personality has garnered the scorn of her schoolmates; Asuka calls her a "doll" or "puppet."

Although she once only associated with Gendou, she and Shinji break the ice after the battle against Ramiel, and grow progressively closer for a while.