Undoubtedly, the character who has the most frenzied lover, along with Asuka. I think Rei is the one and only character in this anime who is true and pure. She never troubled even after knowing that she has many clones. "I am Me" . She always seen cold and emotionless but it's not because she doesn't have emotion, instead she finds it's hard to express her feelings among the others.

Rei was born to be the pilot of EVA at the very first hand, she needs no reason why. Rei's fave belonging is Gendou's broken glasses, I guess as the clone of Ikari Yui, Rei basically still has the love of Yui to her husband. Even Shinji sometimes remember to her mother when he sees Rei. Instead of living with the others, she lived alone in a mess old apartment. She has a constant expression, monotone voice and rarely smiles. No one seems to be able to understand what she actually thinks about. Rei only smiles to 2 people, they are Ikari Gendou and Shinji. Indeed Rei is holding the key to the end of this anime [watch the movie, The End of EVANGELION].