Things writers think about

...or, perhaps, "things about which writers think". But never mind that. Here's what's been on my mind the last three days; the oft-uttered Voldemort words, "Harry Potter; the boy who lived, come to die."

What part of speech d'you suppose the writer (of the screenplay? I don't know whether those words show up in the novels) intends the word "come" to be in that sentence? I don't care which it is, but I can see three possibilities: verb ("Harry Potter has come to die"); imperative (i.e. an order, as in, "Harry Potter, come to die!"); or an...adjectival verb, I think the term is? A verb being used as an adjective? "Harry Potter is come to die." It'd be neat if it was a deliberate word-play on all three.