The English word "devil", in reference to highly seasoned food, was in use in the 18th century, with the first known print reference appearing in 1786.[2] In the 19th century, the adjective "deviled" came to be used most often with spicy or zesty food, including eggs prepared with mustard, pepper, or other ingredients stuffed in the yolk cavity.[
I have wondered why they were called deviled eggs for a while. Now I have a greater understanding of why some of my WASP and Appalachian family think anything with more than salt and black pepper is "too spicy".
Apparently I'm from the family branch that not only buys Anal Prolapser Hot Sauce from Ace Hardware, but also makes and sells it
