Akira Fudo is just a normal kid in Tokyo, until an old friend of his, Ryo, shows up and turns his world upside down. An upcoming war of demons on humanity is waiting in the wings, however, the only way for a human to fight a demon is with their power. To save the world, Akira and Ryo risk a dangerous ceremony in an attempt to create humanity's only hope: the powerful Devilman.

Akira Fudo, adjusting to his new powers as Devilman, is in for a heap of trouble as his newest enemy sent from the demon world is Sirene, the demon bird, who has more than a few tricks up her feathery sleeves to keep him and humanity at the brink of extinction.

Fear runs rampant throughout Tokyo with the revelation that demons in fact exist amongst us. Paranoia and the darker side of humanity boils onto the streets as people turn on one another, suspecting that anyone could in fact be a demon hiding in human clothing. Amidst the growing tensions, tragedy strikes Akira causing his mind to snap, retreating into his subconscious, allowing his Devilish alter-ego Amon to break free from Akira's cage of flesh and wreak havoc on both human and demons alike.