Things Fall Apart is unique in its use of both Western and native literary traditions. Although Chinua Achebe wrote the novel in English, he drew upon native traditions such as the oral tradition and the use of proverbs, and he imbues the novel with details of native life. However, Achebe was educated in the West (and taught in American universities until an accident disabled him) and also draws upon the Western literary tradition of the tragic hero and the tragic flaw.
Okonkwo, though a revered warrior, reveals his tragic flaw of unreasonable anger and unwillingness to stand up to tradition. Specifically, Okonkwo adopts Ikemefuna, who lives with Okonkwo and is a role model for Okonkwo’s son Nwoye. However, Ikemefuna’s life is demanded as a sacrifice to the Oracle of the Hills. Although the oldest and wisest man in the village (much like the prophet Tieresias in the famous Western tragedies Oedipus Rex and Antigone) warns Okonkwo not to participate in this ritual, Okonkwo is afraid to look weak and kills the boy. This destroys his relationship with Nwoye and leads to his condemnation. As in traditional classical tragedy, Okonkwo recognizes his tragic flaw before his demise.
Paralleling the tragedy of Okonkwo is the tragedy of the Ibu (or Igbo) people as the Western missionaries come and destroy their civilization. Okwonkwo’s story is reduced to a paragraph in the story of the end of the Ibu.
The classical definition of a tragedy is a work of art or literature in which the hero (or heroes) fail in their mission, meet their demise, or lose something of immense value. All three of these things occur within the final pages of Achebe's Things Fall Apart.
If we can surmise Okonkwo's mission in the novel, it seems to be a dogged adherence to tradition, even when that tradition causes him personal pain, such as when he takes part in killing Ikemefuna. As the colonizers gain a foothold among the Igbo, these rituals and traditions begin to fall away, and Okonkwo realizes that his steadfastness may have been for nothing.
Upon realizing that his tribesmen no longer support him as leader, Okonkwo decides he has nothing to live for. He would rather die than be dishonored at the hands of the colonizers and his own tribesmen. He meets his demise through suicide.
Finally, the most pronounced tragedy of Achebe's work is scarcely a paragraph. The final lines of the story are symbolic of the colonizer disrupting and fundamentally changing the culture of the Igbo. As the Igbo become just one of several curiosities described by the white man, something of immense value—an entire culture—is lost.