The irony of Henry
Henry's character is shaped by irony, because the novel is exploiting a common misconception about racism. Henry is an ironic instance of deliberate racism and hatred against his own people. Instead of freeing his community from slavery, he attains slavery and then upholds the institution, buying slaves for himself. This irony shapes the tone of the novel.
Moses's ironic expectation
When Moses expects that Caladonia will fall in love with him, free him, and marry him, he is sorely mistaken. He is so wrong in fact that when he approaches the subject, Caladonia is deeply offended that he would even dare to dream about freedom, let alone marriage with her. She hates him as if she were perfectly different than him, though they are the same. The situation wreaks of irony and caustic satire.
Pride and exploitation
The characters who uphold slavery choose to impose a prideful relationship toward their slaves that quickly infects their character. They feel proud of all their work, but they purposefully ignore the fact that their success is purely derived from stealing labor from their fellow man, and then claiming the profits for their selves. This happens with Henry, then Caladonia, and although Moses is still a slave, he demonstrates the same problem as a middle-manager on the farm.
The deaths of Skiffington and Mildred
When the fight ensues to locate Moses to find out where the slaves have escaped to, Skiffington doesn't just lose that fight—he literally dies. Also, Mildred dies. That would be Henry's mother, so the irony is layered, because Henry chose to enslave other Black people, and he succeeded, but when his own mother tries to help Moses, she loses her life.
The irony of mixed race children
A lot of the ideas that are propagated by the slave owning class are founded in the mistreatment of Black people by dehumanizing them, pretending they are animals. Yet, ironically, there are a bunch of half-black, half-white children running around, living proof that in the eyes of nature, all humans are the same. If they are similar enough to give healthy offspring together, that is evidence that their ideas are unimaginably hateful and wrong, but their closed-mindedness prohibits them from acknowledging that obvious truth.
