Mary Shelley's Frankenstein, was first published (without her name) in 1818. In writing this novel, she created a new form of literature.
Frankenstein is infused with some elements of the Gothic novel and the Romantic movement and is also considered to be one of the earliest examples of science fiction.
Walton does not kill the creature as Victor requested.
Victor dies in Walton's cabin, on Walton's ship. When the ship's captain returns later to the coffin in which Victor's body lies, he find the creature mourning the death of his creator.
When Walton blames the creature for the avalanche of destruction and death he has visited upon the world, especially Victor—accusing him of being the worst kind of hypocrite—the creature defends himself in saying that he had begun life with great hope: delighted by the beauty in the world, caring about and wanting also to be cared for by others. However, this inclination changed as he was abused and ostracized by Victor and humanity. He explains that no one ever understood his pain.
However, he also explains that he will now take care of handling his existence:
Fear not that I shall be the instrument of future mischief. My work is nearly complete. Neither yours nor any man's death is needed to consummate the series of my being, and accomplish that which must be done; but it requires my own. Do not think I shall be slow to perform this sacrifice. I shall quit your vessel on the ice-raft which brought me tither...I shall collect my funeral pile, and consume to ashes this miserable frame...
The creature assures Walton that with Victor's death, he will harm no one else. No one needs to attempt to kill him, for he will do this himself. Quickly he will leave the ship, move to the north—collecting materials for his funeral pyre—and he will destroy himself.
In this way, Walton is not only not afforded an opportunity to kill the creature, but is assured by the monster that he will take his own life. And the monster then departs quickly to do so.
There were two main reasons why Walton did not fulfill his promise to destroy the monster. The first and most important reason was that he did not have to do it. Victor actually came to terms with his life and, through the experiences that weakened his body and spirit, decided to no longer allow hatred to dominate his heart. Therefore, he told Walton that he was no longer interested in destroying or chasing after the creature. In fact, Victor died with a “gentle smile” in his face as if symbolizing inner peace.
The second reason why Walton did not destroy the monster was because the monster told Walton that he was going to go somewhere remote and burn himself. When Victor’s body was lying dead in the room, Walton was shocked to find the monster grieving over his creator, Victor, the same way a child would mourn for a parent. The creature explained to Walton that he was out of place. He had human emotions but he was rejected by the entire human race. He was alone in this world and living with remorse for all the things he did to avenge Victor. He expressed guilt and pain over the deaths of Clerval, Elizabeth, and William. Now, he no longer had the one person whom he could at least consider a “relative”. The relationship between Victor and his monster was hateful and bizarre but, deep within the human side of the monster, there was a basic need for love and care that was not to be fulfilled. Walton believed what the creature said. Hence, there was no need for him to do anything about it.
Walton does not fulfill his promise to destroy the monster because he lacks the resolve to stand up to his men and insist that they continue in their dangerous quest. In himself, Walton would prefer to go on, no matter what the cost, but he does not have the courage to force his men to put their lives on the line as well. Walton says,
"I had rather die than return shamefully, my purpose unfulfilled. Yet I fear such will be my fate; the men, unsupported by ideas of glory and honour, can never willingly continue to endure their present hardships."
Two days later, Walton has bowed to the wishes of his mutinous men, his "hopes blasted by cowardice and indecision." Unable to withstand their demands, in the end, he has found himself unable to "lead them unwillingly to danger."
As it turns out, the objective with which Walton has been charged almost certainly will be fulfilled in the end, without him having to take any action at all. When Victor Frankenstein dies, the monster inexplicably appears on the ship to mourn over his creator's body. Desloate and without hope of ever escaping his station of utter isolation, he tells Walton that he will journey alone to the far north, build his own funeral pyre, and immolate himself upon it. He will "exult in the agony of the torturing flames" in the knowledge that when death finally comes to him, his spirit will at long last "sleep in peace" (Volume 3, Chapter 7).