Devilman: The Birth is a 1987 OVA film based on Yasutaka Nagai's novelization of his brother Go Nagai's manga Devilman. It was the directorial debut of Umanosuke Iida who followed it up with a sequel, Devilman: The Demon Bird in 1990 and the spin-off CB Chara Nagai Go World in 1991.
The OVA starts with a group of beautiful creatures descending from the sky in Cretaceous era Japan, with the intention of wiping out the demon race that had emerged and were ruining God's land. However, they are ambushed and a violent confrontation between the Angels and the demons breaks out, ending in the traitor Satan sending his/herself and the entire demon race into an icy hibernation for several thousand years.
The scene switches to present day where the young teen Akira Fudo is seen tending to the school rabbits, only to find all but one of them dead. Much to his horror, he tries to comfort the distraught rabbit before he is set upon by a gang of thugs. The leader Masa demands that Akira give him the rabbit. When he refuses, one of the gang members Manjiro becomes violent and begins to beat Akira. With Akira still defiant to surrendering the rabbit, Masa is impressed and with the arrival of Miki the gang departs.
Miki tends to Akira's wounds and the two begin to go back to Miki's home when Akira admits he wanted to confess something to her. However they are interrupted by the arrival of the strange and mysterious, Ryo Asuka. Asuka tells Akira that he needed to come to his place, and the two depart. On the way however, Asuka tells him that his father had been killed. At Ryo's home Akira, is told to don on a bizarre demonic mask. Once he does so however he is bombarded by visions of horrific bloodshed, vicious demons, and more. Afterwards, Ryo explains to Akira the origins of the Demon Race.
The two prepare to leave, however on the way the windows are all blown out by a Demons sonic scream. Not long after they are attacked by the squid demoness Texsch, who is then joined by the spider demoness Gardalza. Both come together and quickly lumbers after them. They escape and drive away but they find the road destroyed by Illuge. After fighting their way back to Ryo's home, Ryo tells Akira that the only way to fight a Demon was to become one and tells Akira that they were planning to have a Black Sabbath to turn Akira into a Devilman.
The two go into the underground fall out shelter that had been decked out with music equipment and was holding a large party. Ryo begins to stab the guests with a broken bottle and after killing several of them, the people begin to notice a sudden change as one of the guests transforms into the she-demon Welvath. Then slowly one-by-one, many more of the guests transform and eventually so does Akira. However due to Akira's pure soul and heart he dominates the demons spirit and becomes a Devilman. After doing so, he grabs Welvath by the head and pulls it off her shoulders.
Akira then goes into a bloody frenzy slaughtering the demons without breaking a sweat, until there were none left. However to his horror he finds Ryo unconscious, having been crushed by a fallen demon, leaving Akira alone in a room filled with blood.
- Akira Fudo: A kind, polite and noble boy in his late teens, when approached by his old friend he is forced to accept his destiny of becoming the Devilman.
- Ryo Asuka/Satan: Akira's best friend who was instrumental in Akira's birthing into Devilman, who is also Satan, a powerful fallen angel who had saved the demons from destruction.
- Miki Makimura: The daughter of Akira's adopted parents, she was Akira's best friend after his parents disappeared, and she also had romantic feeling towards him.
- Professor Asuka: Ryo's "father", he discovered the bizarre demon mask and was absorbed by its powers, eventually he kills himself after being possessed by a demon.
- Masa Bokuto: A gang leader who while brutal and rough, he was still noble and admired Akira's courage.
- Texsch: An incredibly powerful and repulsive squid demoness who chased Ryo and Akira down through the halls of Ryo's home.
- Gardalza: A spider like demon who joined Texsch in attacking Ryo and Akira.
- Illuge: A female Harpy demoness who had sonic glass shattering screams.
- Sabbath Demons: Demons who possessed the guests at Ryo's Black Sabbath.
- Welvath: A female demon with horrific features, she is the first to be killed by the newborn Devilman.
- Kagol: A aquatic demon with a singular orange eye.
- Magoad: An antelope like demon with black fur and large horns.
- Jurad: A humanoid demon covered in thin tendrils.
- Wagreb: A large demon with its hosts head still present within her own.
- Vegard: A thin demon with bladed arms and needle like hair.
- Trijask: A large demon with a split jaw and a rock like body.