Rei Ayanami is the First Child (First Children in the Japanese version) and pilot of EVA-00. She is socially withdrawn and hardly interacts with anyone, except for Commander Ikari, who she initially displays some loyalty to but has a much more distant relationship with than commonly believed (she says in Episode 15 that she "doesn't know what kind of person he is", and seems confused by Shinji's belief that the two are close). She lives by herself in a nearly barren apartment in Tokyo-3. Toward the end of the series, Shinji comments that her apartment is very similar to the place where Ritsuko Akagi says she was born.
Throughout the series, Rei's cool and emotionally stunted personality added to her intrigue, and later resulted in arousing the scorn of Asuka, who referred to her as a "doll" or "puppet". Rei is the diametric opposite of Asuka, not only in terms of personality, but also physically. Asuka is outspoken, emotionally extreme, and violent; Rei is the opposite of Asuka on all these major accounts. Asuka has red hair and blue eyes, while Rei has red eyes, but blue hair. This color shift between the characters may also relate to the difference between how they are seen by others and what their true feelings are: Rei is frequently mistaken for being unemotional, while Asuka feigns arrogance to hide her insecurities. Rei and Asuka are believed by many fans to be caricatures of the respective female ideals of Japan and Europe. Rei also shares the traits of light hair, pale skin, and red eyes with Kaworu Nagisa, leading some fans to suggest that these traits are angelic in nature, and leading other fans to believe that these characters have albinism. The show's character designer, Yoshiyuki Sadamoto, later said that these features exist solely to make Rei look more "distinguished" from the rest of the cast, though he did not specifically mention any of these theories. Rei describes blue as "agreeable" and red as the color that she "hates". She says that she dislikes eating meat, but does not call herself a vegetarian. Her color and food preferences might be due to an association with blood, which LCL is known to smell like, or due to some aspect of her origins, though these possibilities are pure speculation. It can be noted that the series creator, Hideaki Anno, is also a vegetarian.