Majnoun's First Words to Nira
When Majnoun speaks his first words to Nira, she is immediately frightened and runs away from him. In response, it only occurs to Majnoun that "perhaps [...] there was some subtle, accompanying sound that he'd missed [in talking to her]," and he even goes so far as to think "at most, the man put an arm around her shoulder when speaking. Perhaps, then, he ought to have touched her before saying 'yes'?" (45). This is ironic because Majnoun is clearly unaware of how truly unusual it is for a dog to speak to a human being as he did. Moreover, it holds an additional ironic valence insofar as this exchange of words between Majnoun and Nira causes her to leave him at a clinic overnight, but their intimacy later in the novel will ultimately prove to be one of the most redemptive and enriching things to come out of the gods' wager.
Atticus' Downfall
In Chapter 2 and 3, we learn of Benjy and Atticus' twin realizations that the top and bottom of a social order are dependent on one another. Phrased most concisely in Chapter 3, "the weak [are], after all, of more than passing importance. Something was 'off' without [submissives] on the lower rung" (94). It is a source of irony, then, that the very thing responsible for the death of Atticus is an ingenious and duplicitous action taken by someone at the bottom of the social network. Atticus is the obvious leader in all physical matters, but in Benjy, he is brought down by someone who is easily mounted, taken advantage of, and chased away.
Benjy's Downfall
Benjy's death is, in itself, a great irony. Not only is it ironic in the same way that Atticus' death is ironic—that is, in that it comes from the opposite end of the social order (and, specifically, as a result of a wish made by someone that Benjy victimized)—but it is also ironic insofar as Benjy causes his own death through his haughtiness. After coming to an inflated sense of his own importance after witnessing Randy and Clare engage in a kinky sexual display, Benjy begins to think that he is the master of the house and is ultimately abandoned by Clare and Randy when they leave their home and skip rent. This, of course, sets off the chain of events that will lead Benjy to starve and be so desperate as to consume poison, which ultimately kills him.
Apollo's Interventions
Apollo's final interventions against Prince also prove to be deeply ironic in effect. When Apollo blinds Prince, he has no idea that this very blindness will instill a sense of purpose in Prince that gets him to his final home. Moreover, when Prince is able to teach his final master an excerpt of one of his poems and Apollo strikes him deaf, there is irony in the fact that this has no effect on Prince's happiness at death, which is itself fueled by the sensation of someone (likely his master) reciting his own poetry. Thus, the "Two Gifts" of the last chapter are not only the two mercies shown to Prince by Hermes, but also the failed curses that Apollo has tried to levy at him, each of which results in a different blessing for Prince.