A shy teenager living in Japan while his parents work abroad, Akira absorbs the powers of the devil Amon thanks to his friend Ryo Asuka.

Then as the self-proclaimed title character Devilman (デビルマン, Debiruman), Akira starts fighting numerous enemies hidden in the world.

Nagai aimed in his take of the Devilman to portray the suffering of a demon, though focused more on the chaos of wars during the climax.

[1] Originally, Nagai designed Devilman to focus solely around Akira's transformation into a fighter, and the violence resulted from having this type of dark character.

[2] In regards to Akira's Devilman persona, Nagai did not aim to give him a "nightmare"-like design but ended up writing accidentally in a similar fashion to the mecha Mazinger Z.

For the anime adaptation, a different design was provided for Devilman which consisted of underwears much to Nagai's disliking.

He also wanted to explore the love triangle between Akira, Ryo, and Miki ever since he read the original manga version of Devilman.

[6] While Akira's characterization remains consistent in the plot, Yuasa wanted to contrast him with Ryo, who he felt was more important in this version based on his actions.

[10][11] In time, the demons launch a world war against humans, which triggers mass panic and paranoia across the planet.

To make things worse, a crazed mob murders Miki and her brother and Akira sees their corpses on display.

20 years after the extinction of the human race, Akira engages Satan in battle, after which his army is defeated and he dies at the hands of Ryo.

His dismembered body remains lies on a rock next to a mournful Satan as God's angels descend upon earth.

[12] Go Nagai also wrote the manga Shin Devilman in which Akira and Ryo time-travel and encounter General Custer and Adolf Hitler.

Meanwhile, a bigger threat emerges when Dr. Adams, a Black Ghost scientist unleashes his new line of high teen Cyborg models against 009 and his friends.

[19] However, SNK artist Nona said he found it difficult to design Kyo as a heroic character, as he did not view Akira Fudo's portrayal fitting of a hero.

[21] Anime News Network initially referred to Akira as an appealing hero based on his kind demeanor, but criticized his relationship with Miki due to how she berates these traits.

As a result, when Akira becomes a more violent person due to absorbing Amon, the review believes Nagai was expressing the idea of a man undergoing growth but still retaining his kind self.

Although Akira and Ryo's relationship is not fully explored, the review felt there was a homoerotic tension between them that was interesting for readers.

[22] Jason Thompson from ANN stated that Akira's inability to save Miki and her family plays "like a visualization of a child's nightmare".

[25] ANN agreed in regards to long-awaited Devilman transformation but found Akira's motivation to fight devils simplistic.

Spinning Image enjoyed the amount of violence that occurs when Amon takes control of Akira and how in the climax the two split to decide who will be the dominant Devilman.