Ritsuko Akagi (赤木 リツコ Akagi Ritsuko?) is a fictional character from the Neon Genesis Evangelion franchise. She is Nerv's head scientist and is heavily involved in the repairs and maintenance of Tokyo-3's defences against the Angels, particularly the Evas.
She is the daughter of Naoko Akagi, the developer of the MAGI supercomputer system which controls Nerv. In many ways, Ritsuko is living in the shadow of her mother, whom she both admires and despises. Naoko was the head scientist working on the Evangelion project before her death, and Ritsuko is continuing the work her mother began with the Evas, as well as continuing the development of the Magi supercomputer system. Flashbacks to a teenaged Ritsuko reveal that she is a natural brunette, just like her mother.
Ritsuko is extremely intelligent, with a strong dedication to her work and a stoic, detached attitude which is frequently contrasted against Misato Katsuragi's hot-headness, especially during Eva combat. Her occasional jibes at Misato are a source of comic relief in the series. She has a great affinity for cats, and Misato chides her at one point for substituting her cats for human affection. She also is a heavy smoker, as evidenced by an ashtray on her desk filled with cigarette butts stained by her lipstick.
As revealed in flashbacks, she was one of Misato's first friends in college, following the Second Impact. Ritsuko was also friendly with Ryoji Kaji; while receptive to his flirting, the series gives no indication that they were ever romantically involved. As the series progresses and Kaji informs Misato of the truth of the Human Instrumentality Project and how much information has been concealed from her, Misato and Ritsuko's friendship dissolves. This fracturing is accelerated by frequent (and sometimes violent) clashes between the two over the lives of the Eva pilots during combat, as Ritsuko is willing to sacrifice the pilots if the situation appears to warrant it while Misato is dedicated to the pilots' survival. Along with Gendo Ikari and the Deputy Commander Kōzō Fuyutsuki, she is the only person at Nerv fully aware of the Evas' true nature and the purpose of the Human Instrumentality Project. It is revealed in the later episodes that Ritsuko was romantically involved with Gendo, as her mother was before her. However, she eventually realizes that Gendo is using her in the same way that he used her mother, and that he cares about Rei more than her. In revenge, she destroys the Dummy Plug system in front of Misato and Shinji. As a result, Gendo has her incarcerated within the GeoFront.
The End of Evangelion
In the opening scenes of The End of Evangelion, after Seele attempts to hack into Nerv's MAGI supercomputer, Ritsuko sets up a temporary countermeasure that halts the takeover, forcing Seele to use the JSSDF to attack Nerv directly. Later, she confronts Gendo and Rei Ayanami in Terminal Dogma, and, with Gendo holding her at gunpoint, attempts to activate Tokyo-3's self-destruction capabilities to stop Gendo from initiating Third Impact. However, the command is overridden by Caspar, the third MAGI personality, which was modeled after Naoko Akagi as a woman. Gendo speaks an inaudible confession to Ritsuko - to which she responds "Liar" - then shoots Ritsuko in the chest, killing her. Shortly afterwards, an image of Rei appears over her corpse, which has fallen into the lake of LCL underneath Lilith. No definite answers have been given as to why Caspar rejected the self-destruct command. In the series Ritsuko confessed her hate of Naoko "as a woman," and just before Gendo's confession to her, she says that "her mother" had betrayed her, not Caspar.
Rebuild of Evangelion
Ritsuko is much more of a background character in Rebuild. Regarding the first film, Evangelion: 1.0 You Are (Not) Alone Ritsuko is primarily seen discussing with Misato. The only insight into her character is a very subtle hint that she might be having a relationship with Gendo. In Evangelion: 2.0 You Can (Not) Advance Ritsuko takes on a closer role to her series counterpart, with brief moments of character development occurring between her and Misato, along with Kaji.
Adaptation by Sadamoto
There is little difference between Ritsuko's portrayal in the anime and in Yoshiyuki Sadamoto's manga. However, in the manga her disdain of Rei is more evident. At one point, during one of Rei's medical checkups, she loses control after Rei rebukes her and tries to strangle Rei. Realizing that she was acting like her mother before her, she stops herself from killing Rei, but warns Rei against telling anyone what happened.
In flashbacks in volume 10, it is revealed that Ritsuko witnessed her mother killing Rei I and committing suicide by leaping from the top of the MAGI computer core. Also, Gendo approached Ritsuko on the day of her mother's funeral and asked her to take over Naoko's duties at Nerv.
Shinji Ikari Raising Project
In this series, Ritsuko assists Kaworu with his covert operations in Nerv and Shinji's school, where Ritsuko acts as the school nurse.