Rei Ayanami is an introverted girl chosen as the pilot of a giant mecha named Evangelion Unit 00, which is used to fight against large monsters called 'Angels'. Rei is an enigmatic figure whose unusual behavior, as well as her 'unusual' appearance, astonishes her peers. Though after a few years, she has gained quite a lot of weight. Rei is a taciturn girl who limits relations as much as possible and mechanically executes any order given to her, even if particularly cruel. She is introverted, socially detached and laconic. Rei seems to be socially withdrawn, emotionless, and rarely interacts with anyone, except for Gendo Ikari, the supreme commander of NERV, to whom she initially displays loyalty but with whom she has a generally distant relationship. Rei is also shown to have an interest in psychology and genetics. She can also read in German. She approaches problems systematically and speaks like a robot, or just nods. Her facial expressions are subtle, and she rarely speaks beyond what is necessary.