There is a huge theme of duality in Sailor Twain, Or The Mermaid In The Hudson and the readers most note it toward the end of the graphic novel.
All the characters in the comic have a dual image of themselves, the good and the bad side. For some, it might be literal (meaning they’re split in half) and for others their other half is a completely different character.
Take Pearl, Twain’s lovely wife, and the Mermaid. Pearl is the good side, she’s the light that is Twain’s genuine love, she’s caring and patient and the love of his life. The Mermaid on the other hand is his temptation, she has a certain darkness, and is completely selfish. While Pearl genuinely cares for Twain’s well being, the Mermaid just uses him and everyone else she encounters to get what she wants, a curse taken off her.
Captain Twain serves as Lafayette’s counterpart in many ways. Captain Twain is the responsible and bland captain that keeps to himself. He prides himself on being a better boss than Lafayette since all Lafayette seems to do is mess around with women on the boat. Lafayette is cheeky and all over the place and serves as what Twain wants to be and what all his temptation is leading him to while Twain is what Lafayette used to be and truly is beneath all his inner conflict.
Beaverton and Lafayette are also counterparts to one another, but not like the previous pair. Twain and Lafayette mirror each other in their ethics and way of life while Beaverton and Lafayette mirror each other as soul mates. Beaverton represents the life that Lafayette wants to lead, but he can’t since he’s bound to the sea. Lafayette is a marvel in Beaverton’s eyes since he’s living the life she writes so much about but doesn’t dare dwell in.
In the end of the book, the dualities of characters takes a literal turn and it is explained how half of a person is taken by the Mermaid to the sea if they hear her sing while the other half remains above. The theme is evident throughout all of the graphic novel and many characters act as another’s mirror, but the three pairs mentioned represent some of the deepest reflections of the characters and their morals.