The laws regarding parody and quoting are the same everywhere in America, as far as I know, and dA is based in America. Publishers can put restrictions on just how much can be quoted from their books, but there is a minimum allowance as long as you give proper credit. But, as dA isn't actually a publisher, I don't think that even applies.

In a nutshell: You're fine. Go for it. {= )

~Neshomeh