The end of the novel returns to the written-letter format that characterized the beginning of the novel. Walton mentions that Frankenstein went back over the notes and revised them and made sure they were accurate. A few letters later, Walton writes that he must go and investigate a strange, almost-human like noise coming from Frankenstein’s room. The next paragraph begins with his return to writing after some events have occurred.
What you have here, then, is an indication that these letters, while they may have been thought about extensively beforehand, are written down exactly as they were, unedited. He did not write drafts and then go back and rewrite them (or, if he did, he disguised the fact). The spontaneous (or, at least, extemporaneous) nature of these letters mirrors that style that many bloggers write in (in my observations across the entire internet, none of which I will link to here because I think that if you’ve read any small number of blogs, you know what I’m talking about) - the “This is straight from my mind, unedited, and therefore more purely ME” aesthetic. Spell-check is unauthentic!
What follows this most interesting paragraph break is a telling of the events that occurred during that paragraph break - Walton’s meeting with the monster at the side of Frankenstein’s deathbed.
The monster speaks to Walton, who then immediately returns to his room to finish his letter, the conversation fresh in his mind. This is important. Every other time the monster has spoken in the novel, it has been through Walton’s written account of Frankenstein’s oral recounting of the monster’s words. They are interpreted by Frankenstein as being dishonest - Walton, who through virtue of his loneliness and desire for companionship was predisposed towards believing Frankenstein’s account. Walton rejects the monster’s point of view because of his relationship with Victor, and what Victor told him about the monster’s persuasiveness. Walton does not want to believe that the monster actually feels guilty - he calls him a hypocrite.
Walton never questions Victor, never asks if he can be trusted. At the beginning of his tale, Victor relates that when creating the monster, he was in the grips of a kind of mania. Focused solely on one thing, his perspective on his goal was unchanged for two years, until he reached it. Keeping this in mind, what does one make of his single-minded pursuit of the monster?
The monster’s behavior has been that of a petulant child - wanting to make his sole parent pay for mistreating him. Unlike a child, though, he has both the intellect and the physical strength to act destructively on his impulses. Victor believes the monster has justified his behavior by distancing himself from society, by pointing out that if a man would kill him guiltlessly because he his not human, then he is freed from any obligation not to kill humans, simply because they are not the same as him. He goads Victor along, providing him with food or clues on where he is headed next, playing on Victor’s guilt for the death of his entire family (excepting his brother Edgar, who simply drops off the face of the narrative).
When the monster talks to Walton, he does not claim innocence of any of the crimes. Instead, he asks why he is the sole villain in the narrative - why all those who have rejected him are absolved from any guilt. He also makes another mention of the state of the devil in Paradise Lost - he may have been cast out from Heaven, but at least he was not alone.
We are presented here with the least refracted representation of the words of the monster (coming to us only through the lens of Walton). Walton intersperses his own interpretation of the monster’s meanings with his explanations. The monster claims to feel guilty, Walton does not believe him. We as the readers are here given the room to believe the monster or not, regardless of Walton’s interpretations. The conversation is fresh enough in his mind that one can trust the accuracy of the words.
After the conversation, the monster jumps out the window, intent on reaching the north pole, where he can dramatically commit suicide atop a burning pyre. Or does he?
Walton’s last letter is one of disappointment - his friend has died, and his crew has threatened mutiny unless he agrees to turn the ship south once it has escaped from the ice. He reaches the aforementioned “most-interesting” paragraph break, goes to meet the monster, and returns to write a paragraph ending with, “the tale which I have recorded would be incomplete without this final and wonderful catastrophe.”
Walton’s expedition has failed - he will return from the northern seas with nothing to show for his efforts except a story that was told to him by a dying man who very well may have been mad. A story that he, himself has no part in.
But what if he, too, faced the monster? Stood his ground, criticized the monster for his destruction of a family, and also showed that he was unable to be swayed by the persuasive lies of a hypocritical beast? Yes, he was a failure as a sea captain, but perhaps his voyage could be known for something else. Something fantastic - and he, the best friend of the man to whom most of the events had happened, and also the last person to encounter the monster before his suicide, the only one there to relate these amazing stories to the world.
And all he’d need is a great ending that would tie him into the main meat of the story, to place him in the same physical space as the monster. So what if it were a little fudged - there’s always a chance that Victor’s specific details weren’t exactly right.
The “spontaneous” interruption of the letter is followed by Walton’s showdown with the monster, which neatly ties up any loose ends, suggests to the reader that any attempts to find where the monster is now will be useless (since he’s going to burn his body at the northernmost point of the world, a place that the failure of Walton’s expedition has shown to be all but unreachable), and echoes things the monster has said before (right down to the exact same Milton reference). It’s an ending that, to Walton, seems both “final” and “wonderful”.
The end of the novel, then, in addition to serving as a good end to Mary Shelley’s story, works as an excellent end to Walton’s. It serves Walton’s need for adventure, for having had an amazing experience. Maybe he fudged a few details here and there - maybe he made up the entire ending. As we have no other window into the story except through Walton’s writing, there’s no way to know for sure.
And maybe Mary Shelley’s Frankenstein isn’t a book about the story of Victor Frankenstein, so much as it is a book about a man named Walton, who on a long sea voyage, for want of a friend (either out of his own desire or to assuage his sister’s concerns about him becoming too lonely) or a justification for an expedition that didn’t meet its goal, invents a man named Victor Frankenstein, and makes himself responsible for telling this man’s fantastical life story.