Darkness at the arch (A story I wrote)

[John V]

Note that sentence fragments can be used in fiction, but such use must be infrequent, and can't be early in the book.

Could you elaborate on the part in bold?

Sure. If you use a sentence fragment early in the book, readers will think you're incompetent and quit reading. If you demonstrate that you're competent for a couple chapters and then use one, readers will give you the benefit of the doubt that it was intentional.

Of course, this mainly applies to unknowns. An established author has, well, already established credibility, and can break the rules on the first page if he chooses.