Here's the history behind the the name. An Englishman by the name of William Underwood set up a small condiment business on Boston's Russia Wharf in 1822. It did pretty well both developing and selling new condiment products. Around 1868, Underwood's sons began experimenting with a new product created from ground ham blended with a mix of special seasonings. They introduced a product line of seasoned meat products including ham, turkey, chicken, lobster, and tongue. They called the seasoning process "deviling," and the Underwood "red devil" was born.
Today many other foods, including eggs and crab, are served "deviled." To be considered deviled, a food has to have a kick from something like Dijon mustard, hot sauce, cayenne pepper or chopped hot peppers.
Underwood's Deviling process holds U.S. Patent Office trademark NO. 82, granted in 1870, the oldest existing food trademark still in use in the United States. The exact"deviling" recipe remains a company secret to this day.