Mentos are objects, so IMO they fall under the content category.
Unless someone makes a sort of Mentos Man (à la Pepsi Man) I think mentos should be content, because it's describing what's actually in the story (candy) rather than "intellectual copyright" - the storyline/character design of a franchise - thus there shouldn't be any difference between, say, dango, and a monopolized (brand-name) food like mentos.
Now that I think about it, isn't "oblivion" the same as "the elder scrolls"? I think having them as separate tags is useless from the point of view of yukkuri. We're not Danbooru so if a mod for The Elder Scrolls is for Oblivion or Skyrim makes no difference.