What literary device is: "A drop of night"?

I’ve read a ton of novels and there’s nothing I like more. One thing I’ve noticed that a lot of them have in common is that sometimes, early in the story, the author seems to...

I don't remember the name of the book, but I remember it was either a sci-fi or fantasy book. It had a greenish-black mixed cover with a single character on it that looked sort of ...