1) American mystery novel 2) At no time hereafter 3) Cry associated with Poe 4) Famous word of a bird 5) Last word of The Raven 6) Never again 7) Not again 8) Not even once thereafter 9) Not ever again 10) Opposite of eternally 11) Poe word 12) Word averred by a bird 13) Work about Edgar Allan Poe Found on https://www.crosswordclues.com/clue/nevermore
Nev'er·more` adverb Never again; at no time hereafter. Testament of Love. Tyndale. « Where springtime of the Hesperides Begins, but endeth nevermore .» Longfellow. Found on http://www.encyclo.co.uk/webster/N/18