The Kudan was a ancient yōkai from Japanese folklore, commonly depicted as either cows with human faces, or humans with cow heads. It was a monster that foretold disaster being seen only before a great war would have started and dying when it ended.

History in Devilman Lady

The Kudan was used as an example by Seiji Hayami when talking to Jun Fudo about the ancient Grumech god of war Vlava who had a similar idea to the Kudan, as well as appearance.