The Kamen Riders, known as Oni, battle man-eating beasts called Makamou with "pure sound". One of the Oni, a man named Hibiki, ends up having a "teacher-and-apprentice"-like relationship with Asumu Adachi. A young boy unsure of himself and is at a crossroads in his life as he transitions to high school, Asumu learns to be an adult through watching Hibiki and the other Oni as they all train together to hone their skills in fighting the Makamou and the homunculi aiding them. However, the sudden raise of Makamou numbers proves to be a prelude to an upcoming calamity.
Kamen Rider Hibiki began with Shigenori Takatera as the Toei producer, however, Shinichiro Shirakura, who though having participated in other Heisei Kamen Rider series, had no involvement whatsoever in the Hibiki production, was appointed producer of the film Kamen Rider Hibiki & the Seven Senki, eventually replacing Takatera in the TV production from episode 30. The writing staff also changed; Tsuyoshi Kida and Shinji Ōishi were replaced by Toshiki Inoue and Shōji Yonemura, who had worked with Shirakura in Sh15uya and other Heisei Kamen Rider series.
In addition, personalities such as Sensha Yoshida, a renowned manga artist; Hiroshi Yamamoto, a video-game designer; Masao Higashi, a seasoned television and movie critic; and many others published severe criticisms in their personal blogs because of this. Even the show's star, Shigeki Hosokawa, who portrayed Hibiki, stated in his personal website that Inoue’s scripts "needed adjustments" and that this whole staff change was "fraudulent". With the first production staff, Hosokawa would join the writers meetings and give suggestions, however Hosokawa could not give his opinion in the second production staff meetings due to time restraints.
In an interview published on TV Asahi's main website, Hosokawa stated that the script for the final episode was rewritten on the final day of filming. He later said that the script was sent in so late that it arrived on set as the final battle was being filmed. This finale was scrapped and then a new ending that, according to Hosokawa, was nothing like the intended ending, was filmed. Later in the interview, Hosokawa said that the Oni suit used by Kiriya was a kitbash of two new suits made especially for the characters of Asumu and Kiriya. Hosokawa said that this was the most upsetting change to him as the final script had been rewritten six times at that point and all but the filmed version contained both Asumu and Kiriya becoming Oni.
In January 2006, at the Kamen Rider Super Live, Hosokawa stated that the series was "essentially an incomplete process" and that "it should not have ended that way". Mitsu Murata, who portrayed the Douji characters, declared on his blog: "I cannot forgive them, I want to continue his idea", complaining about the removal of Takatera as producer. These declarations caused an unprecedented storm within the professional tokusatsu market and many of Toei's executives were berated for allowing a series to be handled in such a manner.