Manjiro is the protagonist of the novel. He interprets events and interactions with other characters based on his culture, which supplies unique insights into the world and American culture around him. Although he faces discrimination for his race, he is kind, and his relationships with other characters create the emotional beats that sustain the narrative.

As suits an adventure-action novel, Manjiro’s curious character is key to his development. He is immediately shown to be aware of these traits. The narrator says, “He knew he should not ask so many questions, but he couldn’t help himself” (2). Manjiro’s constant questions are both criticized and welcomed by others, but they always help him grow. While his curiosity drives his character growth, his spirit of adventure and desire to see new worlds drives the plot. The narrator frequently uses metaphors of sight: “He had, in fact, found a new way of seeing the world. Not with fear, but with wonder” (86). His desire and ability to see pushes him to new frontiers.

Manjiro’s social status also characterizes him. His upbringing as a peasant shaped his humility and dutiful nature. He is respectful to others almost without exception, making the scene where he stands up to Davis the clearest sign of character growth.