What inspired Neon Genesis Evangelion?

Evangelion has the crispest creator-stated formula in this entire Library, and it comes from the man who designed its faces. Character designer Yoshiyuki Sadamoto, speaking for the staff in material from the Evangelion Volume 1 book (archived by EvaGeeks), said: "Both Anno and I, our generation, was influenced by Go Nagai, so making something on a grand scale meant it ended up like Devilman... It might not be an exaggeration to say that if you add Ideon and Devilman together and divide by two, you get Evangelion."

The halves are identifiable. From Space Runaway Ideon (1980), Yoshiyuki Tomino's bleak mecha epic, comes the apocalyptic machinery and an ending that spares no one; the team even wanted a title in Ideon's mold. From Nagai's Devilman (1972) comes the intimate apocalypse, demons, possession, and a world ending at human scale.

Sadamoto confirmed the debt at the other end of the story, too: in his Der Mond interview he said he and Hideaki Anno wanted an ending similar to Devilman's. The formula held from title to finale.