Asuka is only one quarter Japanese, which accounts for her Japanese name but European appearance. Asuka is a native of Germany, having been raised there, though her nationality is technically American. Asuka's native language is German, and in both the series and the manga she tends to curse in German. She is a child prodigy and has earned a university degree in an unspecified field as a teenager; she also speaks fluent Japanese, but has trouble reading and writing kanji. She is characterized by her fiery red hair and equally fiery temper. Asuka is very proud of being an Eva pilot, and near-constantly wears her A10 nerve clips in her hair, because she wants everyone around her to know that she is a pilot. Asuka's iconic catch-phrase (always directed at Shinji) is "anta baka?!" (あんたバカァ?!), "anta" being a contraction of "anata" meaning "you" and "baka" literally meaning fool or idiot. The official English dub renders this as "What are you, stupid?!"
Her mother, Kyoko Zeppelin Soryu, was a scientist of GEHIRN's German branch of the Evangelion Project. When Asuka was four years old, Kyoko participated in a contact experiment with Unit 02 similar to the experiment performed by Yui Ikari with Unit 01. She survived the test but became insane, believing that Asuka's doll was her daughter and refusing to acknowledge the real Asuka, referring to her as "that girl over there." She eventually commits suicide by hanging herself; Asuka found her body when she went to tell Kyoko the good news that she had been chosen to become an Eva pilot. After Kyoko's suicide, Asuka's American father remarried a German doctor. This new mother is immediately repelled by Asuka's defensive nature, and finds herself unable to become attached to her. While talking to Shinji Ikari, Asuka states that she doesn't hate her stepmother, but she feels as if she could never replace her real mother.
During Kyoko's funeral, Asuka's grandmother had said to Asuka that she was "a strong girl", but it was alright if she needed to cry. However, Asuka protested against the idea and told her grandmother that she had to take care of herself for now on. From that day on, Asuka promised herself that she would never cry again. This causes her to repress a great deal of emotions, not to mention the emotional scarring that came from her mother's illness and death, leaving her twisted and vulnerable towards the end of the series.
Asuka graduated college despite being a minor. What degree she received is not stated. She is attending school with the rest of the children in order to learn kanji.
The series' creators have described Asuka as a girl "who seeks to put herself above all others": in the very first scene Asuka appears in, she is standing on the control tower of the aircraft carrier, physically standing high above the landing pad where Shinji, Misato & Co. exit their helicopter transport. This also occurs later in this same episode, when Asuka feels driven to show off Eva 02 to Shinji, and is compelled to stand on top of Eva-02 to look down on Shinji far below. Also, when Asuka initially finds Shinji and orders him to come see Eva-02 with her, she is standing at the top of an escalator he is riding.
Asuka and Kyoko
After her contact experiment with Evangelion Unit-02, Kyoko Zeppelin Soryu went insane and committed suicide. Before Kyoko killed herself she would talk to a doll that she thought was Asuka and ask her daughter to die with her, as Asuka's father wanted neither of them. On the day she was chosen to be an Eva pilot, the young Asuka opened the door to see that Kyoko had hanged herself along with the doll. When her mother told Asuka that she was not wanted, and so should die with her, it might have been the impetus for Asuka’s entire teenage personality, as she certainly tries to make people "notice" her, and also to assert her independence and adulthood.
As an Eva pilot
As a consequence of these needs, Asuka loves to pilot an Evangelion because it gets people to pay attention to her, but beyond that, Asuka seems to have a genuine zest for piloting, because it makes her feel powerful. Asuka is so proud of being a pilot that she constantly wears her Interface Headset, even when in a swimming pool or at a hot springs bath. But because Asuka does not pilot out of a pure warrior’s spirit, she is trapped in the same bind that Shinji Ikari is, of being unable to have an identity separate from an Evangelion. Asuka is also the character with the most consistent "color scheme" in the series. Her Plug suit, Interface Headset, Evangelion, and hair are all red. This might be meant to symbolize her temperamental, passionate personality or to solidify the sense of identity she needs from her Eva. This can be further supported by the fact that she is also the only Children whose number designation matches with her Evangelion's. Asuka is so identified with piloting that the loss to Zeruel in Episode 19 devastates her. This, followed by a mind-rape from Arael that forced Asuka to relive childhood trauma, and then being rescued by Rei Ayanami, whom she despised, started a breakdown that lead to a nearly comatose state in which she cared about nothing.