[3] Neon Genesis Evangelion production studio Gainax then contacted Hidetoshi Satō and Toshiyuki Ōmori to write an original piece in place of the soundtrack's main composer Shiro Sagisu.

[12] The song begins with the voice of a woman who advises a young man to behave like an angel without mercy, encouraging him with the cry of shin wa ni nare (神話になれ, lit.

[14] Oikawa also took inspiration from the manga A Cruel God Reigns (残酷な神が支配する, Zankoku na kami ga shihai suru),[2] which was written by Moto Hagio and was being published at the time, and inserted the term tenshi (天使), which usually refers to the angels of Christianity.

[15] An additional religious reference, the verse "Watashi wa sō jiyū o shiru tame no baiburu" (私はそう自由を知るためのバイブル) ("This is the Bible with which you will learn what freedom is"), was added to the lyrics.

[18] According to Comic Book Resources's Devin Meenan, the lyrics could refer to Yui Ikari, mother of protagonist Shinji who protects him during the events of the series, or Misato Katsuragi, his superior who encourages him "to come out of his shell".

[23] On October 25, 1995, "The Cruel Angel's Thesis" was released as a single in two versions: in the first one, with a cover price of ¥1,049, it was accompanied by a song by Takahashi entitled "Tsuki no meikyū" (月の迷宮, lit.

[54][65] Comic Book Resources' Eduardo Luquin praised its tone, writing, " 'Cruel Angel's Thesis' is a hype train that starts the trippy trip to the destinations known as philosophy, religion, and teenage angst.

[67] Matt Fagaly of Crunchyroll and Tom Pinchuk of Geek & Sundry praised the contrast between the dark, pessimistic themes of its parent series and the song's lighthearted tone.

[91] In August 1997, the Japanese magazine June, specialized in shonen-ai homoerotic manga and anime, issued a volume entitled Zankoku na tenshi no yō ni (残酷な天使のように, lit.

[94] In 2018, Evastore, an official store entirely dedicated to the series, advertised the release of the single in a restored digital format and produced new Evangelion-related merchandise, such as t-shirts,[95][96] posters,[97] and metallic postcards.

[99] On December 26, Takahashi performed "A Cruel Angel's Thesis" at the opening of an izakaya club dedicated to the series;[100] a drink named "Zankoku na tenshi no these" was also released.

Director Ondřej Hudeček stated that he had originally been introduced to the series at around the same time as the Nagano Olympics, and that he chose to use the "The Cruel Angel's Thesis" and an Evangelion-themed opening because he wanted to incorporate references synonymous with his experiences of the late-1990s.

[118] In 1997, shortly after the end of the anime's first airing and the release of the movie Neon Genesis Evangelion: Death & Rebirth, "A Cruel Angel's Thesis" was awarded the gold and diamond record (named "Million" in Japan),[119] while the edition with "Fly Me to the Moon" was certified platinum.

[121] A remix done in 2009 was also successful; in June and July of that year, "A Cruel Angel's Thesis" became the most popular anisong of the period,[122][123] appeared for fourteen weeks on the Oricon charts, and reached number twenty-two.

[150] Joysound listed it as the most-played song in karaoke in the Heisei period, the previous thirty years of Japanese history,[151] and the second-most-sung anisong of the first half of 2020, after LiSA's "Gurenge".

[160] Hideaki Anno's name appears in large letters in the video's last few seconds, and is seemingly cut off by Eva-01's arms, emphasizing the director's strong imprint on every aspect of the series.

[179] According to writers Sellées and Hernàndez-Péres, the ten sephirot represent "types of human behavior"; consequently, the Tree suggests both religion and psychology, "thus bringing together the two main thematic readings of the series".

[183] Alternating on the screen are images of Eva-01's hand covered in blood and 01 unleashing twelve wings of light, along with white captions on a black background and vice versa, maps, pencil sketches, a drawing depicting Kaworu Nagisa,[184] portraits of Misato Katsuragi, Ryōji Kaji and Ritsuko Akagi,[185] the first Angel Adam, and a luminous red sphere.

[186] The video ends with a text written, according to the official storyboards, in "angelic characters" (天使の文字, tenshi no moji); according to Anno, it represents the Dead Sea Scrolls.

[189] Neon Genesis Evangelion' manga English editor Carl Gustav Horn also compared the calligraphy of the characters to the Sefer Raziel HaMalakh, a grimoire of Practical Kabbalah.

According to Neon Genesis Evangelion: The Unofficial Guide, written by Martin Foster and Kazuhisa Fujie, some viewers were at first confused by seeing the theme song, but after the series' conclusion they noticed that "everything that appeared in the story had been highlighted, flagged or hinted at in the opening sequence".

[203] On October 3 of the same year, Takahashi took part in the unveiling of a reproduction of Eva-01 at Toei Kyoto Studio Park in Ukyō-ku, singing "Zankoku na tenshi no these" on the palm of the humanoid's hand.

[219][220] In ～refrain～The songs were inspired by Evangelion (November 6, 1997), a remix named "Ambivalence Mix" and an instrumental version titled Epilogue de these edited by Tony Orly were added.

[239] Two years later, a new arrangement titled "2017 Version" was included in the anthology Yoko Sings Forever (March 22, 2017);[240] the recording was done live with piano by Marashii and organ by Satoshi Takebe.

[241] In July 2019, "Zankoku na tenshi no these" was also used in the strategy video game The Battle Cats;[242] Takahashi sang only the word nya (にゃ), a Japanese onomatopoeia of meow.

[247] The Chinese broadcaster Shenzhen TV acquired Evangelion for a Chinese-language dubbing; the first translation was not approved by the National Radio and Television Administration, a ministerial agency under the State Council of the People's Republic of China, so the series was translated and dubbed again, removing the contents that were considered inappropriate for a young audience and the theme song was renamed Měilì tiānshǐ de xíngdòng gānglǐng (美丽天使的行动纲领, lit.

Version II)", lasting 4:04 minutes and sung by Kotono Mitsuishi, Megumi Hayashibara, and Yūko Miyamura, voice actresses of the three major female characters of the show, respectively: Misato Katsuragi, Rei Ayanami and Asuka Sōryū Langley.

[252] Hayashibara stated while singing "The Cruel Angel's Thesis" she thought of the scene in which Rei smiles for the first time at Shinji Ikari in the film version of Eva.

[256] Other artists have recorded covers of "A Cruel Angel's Thesis", including Shōko Nakagawa,[257] MIQ,[258] Yōko Ishida,[259] Masami Okui,[260] Shizuka Itō,[261] Mikuni Shimokawa,[262] Toshi,[263] Aya Hirano,[264] Arlie Ray,[265] Ryō Horikawa,[266] Chihiro Yonekura,[267] Akina Nakamori,[268] Maya Sakura,[269] Konomi Suzuki,[270] Kikuko Inoue,[271] and Natsuki Katō.

[272] Music groups, both Japanese and foreign, also performed the song, including Animetal,[273] Anipunk,[274] Globe,[275] Move,[276] Flow,[277] Glay,[278][279] Glory Gospel Singers,[280] Anime That Jazz!,[281] Max,[282] and Roselia, a band from the media franchise BanG Dream!.