Mostly ditto JoseK's answer.
Let me just add: Many real people's names are used this way also. In the U.S., anyway, calling someone "an Einstein" means that he is very intelligent, especially in math or science. Calling someone "Benedict Arnold" means he's a traitor, often used to refer to personal betrayal as opposed to betraying his nation. "Victorian" means very proper or prudish. Etc.
The exact usage varies. For example, if a girl had a hard life but than marries well, people will say, "That was a Cinderella story", but they rarely say, "She is a Cinderella." On the other hand a man who is romantic may be called "a Romeo", but people rarely say "he lived a Romeo story". They might say "it was a Romeo and Juliet story". Etc.
Whether you can get away with making up your own such archetype depends on how well known the story is and how clear-cut the character is. If you referred to someone as "a Darth Vader", with a little context I'm sure people would know what you meant. But if you picked a character from a book that is not widely known and started saying that someone was "a Herbert Fromm" or some such (a name I just made up), of course no one will have any idea what you mean. I'm sure there are characters well known in certain communities and not others. Like if you talked about "a Dominic Flandry" to a group of science fiction fans, many would recognize the character from Poul Anderson's books. But to most it would surely be a highly obscure reference. Etc.