Tension and conflict between settlers and Natives
Not surprisingly, the Natives aren't keen on the European settlers and their ways of operating. When Mononotto's son is killed in cold blood, he swears to take vengeance on the "tribe" of settlers who are responsible (notice that he views it as a breach of honor, which is why he wants to do an honor killing to avenge his son). However, the more individualistic Europeans are perplexed by his aggression. Ultimately, the conflict leads to a blood stalemate where they go back and forth, harassing each other and reopening old wounds, so they never find peace.
Destiny, honor, and fate
When Esther realizes that Hope and Everett belong together, she decides not to stand in their way. This is the novel's final way of pointing to this theme, that various aspects of human life (like romance, career, destiny, and fate) seem to be outside of our control, so we ought not to stand in the way. This theme appears throughout the book in many ways. When Alice is forced to marry Charles, it's still Fletcher who raises her babies (meaning that their fate to be a family prevailed). When the Natives fight against their impending doom, the reader knows from history that their culture will eventually wane under the heavy-handed rule of Britain. And throughout the story, the characters fight for their loved ones and families. This is very similar to the Greek view of fate in that both require tremendous sacrifices from their characters.
Love and life
Another undeniable theme is the inclusion of religion in the novel. The daughters that Alice leaves to Fletcher are named Hope and Faith, and reminder that despite Alice's death, and despite the tragedy of their downfall when they were young and in love, that life will still continue. Fletcher sees the omen and agrees to raise the girls like his own daughters, helping to continue the sacrifices that will lead to their maturity, eventually the kind of maturity that helps Hope to fulfill her fate.
