I am doing a Master's degree in translation. One of my research projects for a terminology class is about proper nouns in expressions. I am currently looking at proverbs in English and French that contain either the words "God" or "the devil" (or sometimes, "the Devil").
I know that proper nouns take a capital, which would seem to exclude using any proverbs where "devil" is not capitalized, yet there is just enough incidence of the word appearing capitalized to make me wonder.
So, after that long-winded build-up, I would like to ask for people's opinions on the subject: is the devil a proper name even if it is not capitalized? Why is the word sometimes capitalized and sometimes not?
Thanks in advance for any insights you may have to bring to the topic.