Kazuya Tsurumaki (鶴巻 和哉) served as a storyboard artist, assistant character designer and assistant director for the Evangelion TV series as well as the director of Air. He started at Gainax as an animator for the series Nadia: The Secret of the Blue Water and has since worked on many other Gainax shows, most notably, as director of FLCL (His first official project as director) and Diebuster (Aim for the top, Gunbuster 2). He also took over after Anno abruptly ceased work on His and Her Circumstances. Tsurumaki is also a director for the Rebuild of Evangelion movies. Because of his heavy creative involvement in Eva, Tsurumaki is sometimes regarded as the "No. 2" of Evangelion production.
In 2001, he attended Otakon where he was asked directly the relevance of Christianity in Evangelion and replied: "There are a lot of giant robot shows in Japan, and we did want our story to have a religious theme to help distinguish us. Because Christianity is an uncommon religion in Japan we thought it would be mysterious. None of the staff who worked on Eva are Christians. There is no actual Christian meaning to the show, we just thought the visual symbols of Christianity look cool. If we had known the show would get distributed in the US and Europe we might have rethought that choice"
In the 2.0 CRC, in response to Yoji Enokido's proposals to have Mari's role greatly expanded and almost entirely replace Asuka, Tsurumaki protested, saying: "I’m an Asuka fan, and I won’t be happy if this scene gets cut". Later he comments that "The reaction of Asuka fans to it would probably be terrifying."