Ezeulu's pride motivates him throughout Arrow of God. He's the chief priest of Ulu, the god that rules Umuaro. Ezeulu plays a prominent role in Umuaro, a collection of six villages in southeastern Nigeria. As chief priest, Ezeulu feels obligated to offer his advice, even though the people don't seem to pay attention to him. When they ignore him, his feelings get hurt. He believes that the people don't have proper respect for Ulu, and when Nwaka challenges Ulu, suggesting that he may be a useless god and the people should get rid of him, Ezeulu is put on the defensive.
Ezeulu's adherence to duty means that he tells Winterbottom the truth when Winterbottom asks how the war with Okperi began. The people of Umuaro are angry with Ezeulu, especially since it causes Winterbottom to rule in Okperi's favor. They are further disturbed when Ezeulu sends his son Oduche to school and to church to learn the ways of the white man. They blame Ezeulu for bringing the British to Umuaro. Ezeulu resents all the backbiting of his neighbors, friends, and kinsmen, and recognizes that it is coming from one source, Nwaka, who is aided by the priest of Idemili.
When things start to go badly in Ezeulu's household, the tension escalates between Ezeulu and his enemies. Ezeulu's son, Oduche, commits an abomination against the royal python, which belongs to the god Idemili. Because of the priest Ezidemili's insults, Ezeulu refuses to do anything special to purify his house. Then his son Obika is whipped by Mr. Wright because he's late coming to work on the road. Ezeulu blames Obika, and his son Edogo criticizes him for choosing a stranger over his own son.
Ezeulu is further frustrated when Captain Winterbottom sends a mysterious message that Ezeulu should appear before him in Okperi. As chief priest of Ulu, Ezeulu doesn't wander far from his hut. But the elders and men of title convince him that he should go, and he sets out the next day, unaware that Winterbottom has put out a warrant for his arrest.
Detained in Okperi for several days, he has a vision of Nwaka inciting Umuaro to rise up and destroy Ulu. Ezeulu sees the people spitting on him, and claiming that he's the priest for a dead god. He suddenly realizes that his battle is with his own people, not with the white man at all. The longer Ezeulu is detained, the better he can plan his revenge. He recognizes that he is Ulu's arrow of punishment. He believes the people need to be taught a lesson, and need to learn to respect Ulu (and, by default, his priest.) While imprisoned for several months, Ezeulu's anger with Umuaro eats away at him, and he plans the punishment carefully.
When Ezeulu finally returns home, the people of Umuaro welcome him. Ezeulu's anger relents, but not completely. He continues to plan his revenge in secret. What is interesting about Ezeulu's revenge is that he clearly tries to separate himself from this revenge; he doesn't see it as revenge for his own sake, but for Ulu's sake. He sees himself as doing Ulu's will, rather than seeking personal satisfaction for his own wounded pride.
The moment for revenge finally arrives. Ezeulu informs the people that he can't name the day for the Feast of the New Yam until he has finished the sacred yams – because he was gone for so long, there are three yams left, which will take three months to eat. The people panic. After three months, their crops will be ruined, rotted away in the ground. They beg him to reconsider, but Ezeulu is steadfast – he must do what Ulu calls him to do.
Famine settles in to Umuaro. Ezeulu's family also suffers. When Ezeulu's son, Obika, dies suddenly, the people see it as a judgment against Ezeulu, who is too proud, headstrong, and stubborn. It gives them the latitude to turn to Christianity, to a god who seems less unpredictable in his need to punish the people.
Ezeulu's pride is what breaks him in the end. Shocked that Ulu would allow Obika to die, Ezeulu begins to wonder if he is being punished. But he can't figure out what he did to deserve punishment. He was only following Ulu's will, no matter how much he personally suffered as a result. His mind wanders, and he becomes delusional.