Make it a point to note what the narrator says sets Marlow apart from other seafarers. How are these qualities of personality important in the story that Marlow eventually tells?

I think Marlow is not as Euro-centric as the other sailors. There is a humanity to Marlow that does not judge everything and anybody who is not white to be savage or inferior. These traits of Marlow help us understand the utter horror that takes place along the Congo. Marlow become the one white character that we can rely on to give us a sympathetic and accurate view of what went on.