Alongside dramatic irony, foreshadowing is one of the primary rhetorical devices that Lovecraft uses to create suspense and add horror to the story. Leaving hints for the reader along the way pulls them deeper into Thurston’s journey, and this personal investment allows the conclusion to have an even greater emotional impact.
Lovecraft begins using foreshadowing to build tension in the very first lines of the story, revealing that Thurston is dead and including a quotation from Algernon Blackwood about the existence of otherworldly creatures. Offering these two details before the actual plot begins allows Lovecraft to establish a key theme as well as the story’s dark mood. Revealing that the story ends with the death of the main character also adds the shock factor, drawing the reader in to discover how and why Thurston dies.
As the narrative begins to unfold, Thurston’s repeated references to maddening “glimpses of truth” hint at the idea that he knows of something incredibly dark and disturbing. Withholding exactly what that thing is, however, invites the reader to speculate and heightens the suspense. Wilcox’s dreams, his bas-relief, and Inspector Legrasse’s sculpture also contribute to the story’s foreshadowing, offering glimpses of Cthulhu’s image and dark power before Lovecraft fully develops it. By the time Thurston finally obtains Johansen’s firsthand account of R’lyeh and Cthulhu, Lovecraft has primed the reader to fear this discovery and understand its severe and tragic consequences. The true meaning of the ominous phrase “In his house at R’lyeh dead Cthulhu waits dreaming” finally becomes clear, and even as the story draws to a close, the ongoing use of foreshadowing encourages the reader to imagine the horrors that will unfold when Cthulhu returns.