The brother enemies
The story of The Fishermen is how a prophecy unraveled the close friendships of four brothers. Ikenna is perplexed by a prophecy concerning his death at the hands of fishermen, and he becomes convinced that his own brothers might be conspiring to kill him. This makes him into a paranoid person, highly hostile and defensive, and he begins to turn his brothers against him. The transformation is riddled with irony, the center of which is that brothers are supposed to be there for one another, but to Ikenna, they are psychic enemies.
The crazy man
The dramatic irony of the insane man's prophecy is that Ikenna will die one day. He doesn't say it will happen soon, but nevertheless, Ikenna becomes an insane person himself, because the realization that he is a mortal who will die makes him so eager to live that he cannot exit the fear spirals. He is driven to absolute madness by the words of a man he called insane. In reality, it is death that undoes him, because the real threat of death is too much for him to handle.
The irony of death
As noted, Ikenna is asked to reconcile with his own death, but instead, he is perfectly perplexed by death. It had never occurred to him. Although he knew the whole time that everyone dies, it never occurred to him that he himself would die, until it was prophesied. This isn't a prophecy about stars falling from heaven, or about hell wasps from the deep; it is a promise of human death. He cannot escape that prophecy because he knows it is true. The painful truth of it was hitherto obscured by the dramatic irony of innocence.
Self-preservation and attack
The book portrays an ironic aspect of human nature. Although Ikenna feels deep betrayal because of the brothers (he is convinced that they are conspiring to kill him), he actually afflicts his brothers with mistreatment. He attacks his brothers in an attempt to defend himself from their potential. Ironically, his self-preservation turns him into a competitive monster. The fear of death makes him into an agent of chaos instead of love. He is like a drowning child trying to stay afloat by drowning other children.
The innocent witness
Benjamin is an ironic witness, because the dramatic irony of human nature is gradually stripped away until finally, he encounters the truth about human nature. He is like the Biblical Benjamin who is implicated in the conspiracy against Joseph, though Benjamin is innocent. Like his Biblical namesake, this Benjamin is implicated in the paranoia of his brother although he has done nothing wrong. He loves his family dearly and doesn't understand why this might be happening.
