How three characters contribute to the novel

I have to write a big essay for English. The paper is due tomorrow, and I really need some help!

Question is; Chose three characters from Heart of Darkness and discuss what each one contributes to the novel. Some example characters are; Kurt's intended, the manager of the central station, the Russian, Fresleven, the Cannibals, the Accountant, Marlow, or Kurtz.

Any info and knowledge is more then welcomed.

Thanks for help!

The Russian gives Marlow and the reader a highly idealized view of Kurtz. Even when Kurtz threatened the Russian that he'd kill him over not handing over his ivory, the Russian did not seem to alter his perspective of Kurtz following that incident. Th accountant further acknowledges the theme of white superiority in the novel. An example is when he finds the bugs not annoying while working but the groans of a dying man anger him as he's unable to work. His lack of consideration comes off rather disturbing to the reader. Lastly, Marlow narrates the story for the reader. Without Marlow, the reader would have no insight of what was occurring in Africa during Europe's imperialism. The reader would be as ignorant as the Europeans Marlow describes at the end of the novel.