"Er isst mit den Frauen."
In trying to research definite articles and cases, I came across a form of dative fem plural "denen' - thus this sentence would look "Er isst mit denen Frauen." What gives? In this case (fem plural dative) is it "den" for usage in definite articles and "denen" for demonstrative pronouns?
"Er isst mit denen Frauen" is an incorrect sentence - "denen" is not an article. You are right about the dative case and that it is a demonstrative pronoun. It could be used like this: Er isst mit den Frauen, denen er einen Brief geschrieben hat. - He eats with the women whom he has written a letter to.
I see :) I do indeed, and I do understand. Since for now I am living in the present ( as in my Duolingo progression only - unfortunately :) I can only appreciate your sentence in theory. I shall strive to get out of my German lingo diapers and start forming sophisticated sentences like the one you provided. Thank you.