The two characters of Kurtz and Marlow are curiously interlinked in this book. Marlow is shown to have a somewhat supernatural fascination with Kurtz from the first moment he hears about him, and his sense of anticipation at finally meeting the man he has heard so many different conflicting rumours about is palpable as he makes his way up the river into the "heart of darkness." In a sense, the two characters could be said to be doubles, or doppelgangers, in that they share a strange link that allows them to be compared and contrasted. In Kurtz, Marlow sees the fate of the colonial endeavour as Kurtz, a white man, went to Africa with such hopes of doing good, but in the end descended in to pure evil. This is something Marlow is well aware of as he gets to know him. Note how he describes Kurtz in the following quote:
His was an impenetrable darkness. I looked at him as you peer down at a man who is lying at the bottom of a precipice where the sun never shines.
The way that Kurtz is consistently associated with darkness indicates his moral degradation. Yet at the same time Marlow finds himself enraptured by his words and the power of his rhetoric. The crucial difference between them however is that Marlow is able to cling on to his sense of moral goodness, whereas the "impenetrable darkness" of Kurtz is something that shows his character is so steeped in evil that he has lost the ability to distinguish between good and evil any more. His final words, "The horror! The horror!", act as a condemnation of both his life and acts and also the colonial enterprise. Marlow of course shows that he is not completely untainted at the end of the story, as his lie to the Intended shows, yet the fact that he is described as a "buddha" as he shares his tale indiates that there is some kind of goodness that remains uncorrupted. The characters are linked through their difference to colonialism.