When the Europeans finally succeed in taking control of the government, then Okonkwo—like a fire without any fuel—dies, a victim of his own nature.
Like a fire, Okonkwo is violent, and burns whatever he touches. Throughout the novel, Okonkwo nags on his wives and son, beats his family, and kills three innocent people—not to mention himself, as well.
In many cases, he hurts his family for trivial reasons.
But over time, the missionaries became increasingly aggressive—even hostile—to the native Umuofian beliefs and culture.
Slowly, the Europeans erode the native beliefs and come to dominate the native society.