Gendo is grief-stricken by the sudden death of his wife Yui, and abandons his son Shinji Ikari to devote himself to a plan named Human Instrumentality Project.

Years later, Gendo asks Shinji to pilot a giant mecha named Evangelion; his pragmatic, cold, and calculating attitude leads him to use any means to achieve his personal goals.

The character, who was originally conceived as a modern version of Victor Frankenstein, is inspired by the personal experiences of the series' production staff, reflecting the absent, emotionally detached Japanese father figure.

[7][8] The special agency Nerv, in particular, was conceived as a metaphor for Gainax studio; Anno also described Gendo as a representation of his shadow, the dark, unconscious side of an individual's psyche.

[9] Gendo was influenced by the personal experiences of staff members, including that of Hideaki Anno,[10] whose father injured his left leg with a power saw in a youthful accident, forcing him to wear a prosthesis.

[12]In the early design stages of Neon Genesis Evangelion, Gainax decided to portray Gendo as a "mysterious person in behavior and words", a staunch defender of the Instrumentality Project, expressive, tumultuous, akin to a twenty-first-century Dr. Victor Frankenstein.

However, Tachiki, while disconcerted by the futuristic setting and plot changes, was helped by his accumulated experience and greater maturity, due to which he acted more frankly and serenely than in the classic series.

Tachiki's throat hurt while he was recording a complicated scene in which he shouts Yui's name and had to raise his voice; the production asked him to convey all his emotions and feelings at that moment.

Vision version of the series and the 1997 films, Gendo is voiced by Tristan MacAvery,[26][27] except for additional parts in the director's cut and Rebuild, in which he is played by John Swasey.

To secretly carry out Seele's plans, Gendo participates in a research group known as the Katsuragi expedition, which leaves for Antarctica to conduct experiments regarding a mechanism known as the S² engine.

After marrying Yui, Gendo changes his surname in Ikari[35][36] and, along with other members of Seele and Professor Fuyutsuki, participates in a United Nations-organized expedition to investigate the Second Impact.

Gendo, unlike the Seele, decides to cause a "forbidden union" between Adam, implanted in his body, and the second Angel Lilith, whose soul is kept inside a girl named Rei Ayanami.

[53] To implement the plan, he enters the deepest section of the headquarters, Terminal Dogma, with Rei and inserts his right hand into the girl's body so she can absorb Adam's embryo.

[59] Shinji, in particular, begins to connect with his parent through the nudging and encouragement of Misato Katsuragi and, to an even greater extent, Rei Ayanami,[60] who tries to bring the two closer together by cooking them dinner.

[65] In the course of the film, Gendo comes into conflict with Wille, a company headed by Misato Katsuragi created to destroy the Nerv, and orders Shinji to pilot the Eva 13, maintaining the same aloof attitude as fourteen years earlier.

[72] At the beginning of production, assistant director Kazuya Tsurumaki instructed mecha designer Ikuto Yamashita to create a scenario in which Gendo and Shinji would clash for eternity, even after losing their bodies.

"[23] To carry out his plans, Gendo uses his subordinate Ryoji Kaji[109] and embarks on a secret affair with Dr. Naoko Akagi,[110] a scientist and researcher,[111][112] taking advantage of her scientific talents.

[125][126] Gendo disappoints his son's expectations during the battle against the Angel Bardiel, in which he has the Evangelion 03 unit destroyed without remorse, wounding and mutilating its pilot Toji Suzuhara, Shinji's friend.

[130] He is then devoured by Eva-01; according to Yūichirō Oguro, editor of extra materials from the home video editions of the series, the Eva-01 visible in the sequence may be an illusion and the scene may symbolize Gendo's success in becoming one with his wife.

[131] According to cultural critic Hiroki Azuma, Gendo's uniform is an homage to Leiji Matsumoto's series Space Battleship Yamato,[132] while his pose with joined hands has been compared to that of Gargoyle, the antagonist of Nadia: The Secret of Blue Water.

[140][141] Writer Andrea Fontana compared the series' theme of Oedipal conflict between fathers and sons to other works in the mecha genre, such as those by director Yoshiyuki Tomino,[142] while Anime News Network's Jonny Lobo compared the conflict between Shinji and Gendo to the world presented by the OVA Megazone 23, in which parental figures are almost absent; according to him, however, Megazone protagonist Shogo Yahagi rebels against the government, the de facto enforcer of patriarchy, rather than an individual like Gendo.

[9] Writer Mark MacWilliams also described the series as a portrait of childhood loneliness in a broken society where the father is constantly working, comparing this depiction to the Japanese family context and children growing up in the 1990s before the collapse of the speculative bubble.

[161] Anno himself compared Evangelion to Ryū Murakami's novel Ai to gensō no fascism, whose protagonist Toji Suzuhara attempts to kill the Japanese prime minister, whom he finds similar to his father, and rapes his mother, who in the novel is Japan itself.

[162] After the conclusion of the series, Gendo emerged as the sixteenth-most-popular male character of the time in the 1996 Anime Grand Prix, a large survey conducted annually by the Japanese magazine Animage.

[187] Bertschy, however, praised his characterization, naming him among the most-memorable antagonists in the history of Japanese animation: "Gendo Ikari is the worst dad ever imagined, and so it logically follows that he is also the most memorable villain.

[188] Comic Book Resources' Michael Iacono similarly named Gendo, for his "diabolical brilliance, all-or-nothing attitude, and deeply flawed character traits", among the best antagonists in anime history.

Kotaku's Richard Eisenbeis appreciated the developments and insights into Gendo's past introduced in Sadamoto's manga version, which he said are clearer and more interesting than the original series.

Anime News Network's Justin Sevakis praised the film's opening scene, in which he visits Yui's grave with Shinji, saying, "There's a warmness here, a feeling of great affection that wasn't so prevalent in the original [series]".

[197] A diametrically opposite opinion was expressed by Nicole MacLean of THEM Anime Reviews; Browne stated she greatly appreciated the dynamism of the fight between Gendo's "egotistical genius" and his former Wille subordinates, which "suits this franchise perfectly".

[227] Fans have renamed his characteristic pose, with his hands joined at face height, the "Gendo pose", which has been copied, homaged, and parodied in other animated series, such as Taizo Haisegawa in Gintama, which is also voiced by Fumihiko Tachiki,[228] Voltron: Legendary Defender,[229] by Stella in Rose Guns Days,[230] by Nifuji Hirotaka in Wotakoi: Love Is Hard for Otaku,[231][232] and by Hayato in an official crossover episode between Evangelion and Shinkansen Henkei Robo Shinkalion.