Karas tells the story of Yousuke Otoha, a former yakuza, living in a fictional version of Shinjuku, Tokyo populated by humans and yōkai (Japanese spirits).

Able to transform into a car, an aircraft, and an armored crusader; the skilled swordsman is to stop his corrupt predecessor, Eko, from taking over Tokyo.

Karas won the Best Original Video at the 2006 Tokyo Anime Award competition, and most reviewers were impressed with the images produced by fusing 2D and 3D art techniques.

[4] The final version of Karas was more of a superhero action story,[5][6] and originally intended for three leading heroes in the same vein as the Japanese period drama, Sanbiki ga Kiru!.

[4] Art designer Hajime Satō created a modern version of the ward infused with a mixture of East Asian cultures.

Western gargoyles and Singapore's Merlion statues decorate the streets, and the buildings are modeled on Shinjuku structures of 2003 while blending influences from the Shōwa period.

The concept behind the health of a city is based on traditional Chinese medicine in which the smooth flow of a body's fluids nourishes its internal organs.

They integrated Celtic mythology into their concept for further symbolisms, treating the city as the male (yang); and Yurine (ゆりね), the manifestation of its will as female (yin).

[15] The early parts of the show proceed in a "mikura of the week" fashion as Otoha (as a karas) and Nue separately fight against Eko's minions.

When Eko launches the last stage of his plan and ravages Tokyo with metal tentacles, Otoha ends up among human refugees in a shelter the chief of police had commissioned.

Otoha carries out Nue's request to kill him and his brother, depriving Eko of his new power source and stopping his entire scheme.

Despite defending his human body and Yurine from soldiers ordered by the Deputy Governor to shoot them, Otoha proclaims himself as Tokyo's appointed agent, who will protect all its inhabitants.

Screenwriter Shin Yoshida sets up a dualism of this idea in the form of two Karas characters; one who believes events are leading to a revolution, and the other viewing them as simply the passing of an era.

Capable of transforming into automobiles and aircraft,[14] they are suits of armor animated by human souls infused into them through Yurine's chanting of a Shinto prayer.

[24] Producer Takaya Ibira explained the presence of ravens in Tokyo and the Tower of London, inspired him and Sato to model the agents of the city after them.

[10] Eko was a nameless character in the initial draft and known as "Another Karas" with a different appearance, although his prosthetic left leg is retained for the final version.

Ibira and Sato chose them to be villains, linking the act of the Karas as agents of the city killing these folklore creatures to traditional Japanese exorcism.

The ghostly head in a flaming wheel, Wanyūdō became a heavily armed skull-on-wheels; and the bull-headed spider, Ushi-oni became a big-mouth, bug-eye, hungry-for-humans predator.

The production team explained yōkai represent the city's culture and functions, and their strengths are inversely proportional to the level of technology of society.

Using the yōkai-human relationship as an analogy for human-human interaction, the team suggested people should be open and make the move, instead of passively staying in the background hoping for results.

[37] CG director, Takayuki Chiba studied keren, a kabuki stagecraft technique using various props to surprise audiences and immerse them in the show.

Ike obliged the team's request for Japanese flavored music, and studied kabuki tunes accompanying actors as they strike their mie (見得), a picturesque pose to establish their character.

[41] He chose Prague Symphony Orchestra to perform the main theme because he felt the background of their city and its people suited the character of Karas.

[31] These extra work and the hybrid 2D-3D approach inflated the budget of the production to three times the usual amount spent on an original video animation.

Manga Entertainment released the English DVD edition of Karas as two eighty-five-minute feature length films, The Prophecy and The Revelation, on April 24, 2006, and October 22, 2007, respectively.

They, however, felt setting the scenes in darkness and obscuring points of interest with smoke or other effects marred the high quality imagery.

Anime News Network stated his long scores set the mood in the scenes with their tone, enhancing the reviewers' watching experience.

[47] Prague Symphony Orchestra's performance of the main theme impressed more reviewers who claimed it brought out the heroic essence of Karas with a sense of power and drama, and enhanced the impact of the quick and intense battles.

[5][9][50] Reelfilm and DVD Verdict were more critical, stating the viewer should not have to resort to reading summaries on the packaging to make sense of a story populated with incoherent battles and characters hard to tell apart from.

DVD Talk commented the blending of traditional 2D drawings and 3D CG was interesting; but with a lacking story, the product is a "triumph of style over substance".