During the mass takeover of the Human population with suicide fusions from Demons a few humans regained their hearts and became Devilmen like Akira Fudo. Together they form the 'Devilman Corps', or 'Devilman Army'. Striving to keep each other and humanity safe from the Anti-Demon militia's atrocious acts. Humans with great mental power such as Buddhist Monks also became Devilmen.