Why doesn’t Okonkwo heed Ezeudu’s warning about not taking part in Ikemefuna’s death? How does Okonkwo justify being there, and what effect does that have on him later?

Okonkwo does not want to appear weak in front of anyone. He does not want to be seen as having an emotional connection, even with his son, that would make him look womanish. Okonkwo justifies the killing as being for the good of the many. Refusing to heed Ezeudu’s warning, Okonkwo kills Ikemefuna himself. Despite his son's cries for help, Okonkwo delivers the deadly blow. This act was the beginning of the end for Okonkwo. The deed eats at his very soul.