Second Child ("Second Children" in the original Japanese versions) of the Evangelion Project and pilots the Evangelion Unit 02. Her surname is romanized as Soryu in the English manga and Sohryu in the English version of the TV series, the English version of the anime movie and on Gainax's website.
Born and raised in Germany, Asuka is shown as being of both German and Japanese descent, as from her Japanese name and European appearance (her nationality is referred to as being technically American).[2] Her mother, Kyoko Zeppelin Soryu, is a scientist of Gehirn's German branch of the Evangelion Project and, when Asuka is four years old, participates in a contact experiment with Unit 02 (similar to the experiment performed by Yui Ikari with Unit 01). Though she physically survives the test, Kyoko emerges mentally unstable, believing a doll she cares for to be an infant Asuka while only referring to her actual daughter as "that girl over there" and even going so far as to attempt to strangle Asuka so that she could "die with me!" (this is implied in the anime[citation needed], while explicitly shown in Sadamoto's manga). After being institutionalized, Kyoko commits suicide by hanging herself; Asuka finding her body when running to tell her that she has been selected to be an Eva pilot. Her American father quickly remarries Kyoko's doctor, with whom he had been having an affair, though Asuka's defensiveness quickly repels her new stepmother and the two learn to tolerate one another while maintaining a cheerful facade of a normal family. Asuka proves to be a child prodigy, earning a university degree in an unspecified field while still a teenager and becoming fluent in Japanese (though she has difficulty reading and writing kanji[3]).

First introduced in episode 8, with the arrival of Eva Unit 02 and the battle with the Angel Gaghiel, Asuka is shown as maintaining a high synchronization ratio and exceptional skills as an Eva pilot, being very aggressive and confident in battle. After first being defeated in battle by Zeruel, Asuka's self-confidence (and, correspondingly, her synch ratio and effectiveness as a pilot) begins to dwindle. This comes to a head in episode 22, when Arael appears and Asuka, burdened by increasingly poor results in synchronization tests, is infuriated by being ordered to serve as backup to Rei. She defies orders and tries to attack the Angel alone, but is overwhelmed by a psychological attack by the Angel, forcing her to relive her painful memories and resulting in a mental breakdown. She loses the will to live and becomes incapable of piloting Unit 02, spending much of the final episodes of the television series in a hospital bed in a catatonic state.

In The End of Evangelion, as Japanese Strategic Self Defense Force invade NERV, Asuka is placed inside Unit-02, which is submerged in a lake within the Geofront, for her protection. As she is bombarded by depth charges, Asuka declares that she does not want to die and, in a moment of clarity, realizes that her mother's soul is within the Eva and has been protecting her all along. Her self-identity regained, she emerges and defeats the JSSDF before being confronted by the Mass Produced Evas. Though she successfully disables all nine opponents, Unit 02's power running out and the infinite power of the Mass Produced Evas' S² Engines (which allow them to remain functional despite being severely damaged or mutilated) finally allow them to eviscerate and dismember Unit 02 using their Lance of Longinus replicas. After Shinji rejects Instrumentality, she appears beside Shinji in the film's final scene.

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