In Mary Shelley's Frankenstein (chapter 24), the creature stands over Victor's lifeless body. The creature (when standing over Victor), witnessed by Walton, stated the following:
“That is also my victim!” he exclaimed: “in his murder my crimes are consummated; the miserable series of
my being is wound to its close! Oh, Frankenstein! generous and self-devoted being! what does it avail that I now ask thee to pardon me? I, who irretrievably destroyed thee by destroying all thou lovedst. Alas! he is cold, he cannot answer me.”
When speaking over Victor, the creature is stating how he feels about Victor. It seems, here, that Shelley is showing the true compassion that the creature truly has. The creature is surely feeling sorry for the death of Victor, both for himself and Victor.
Later, when addressing Walton, the creature admits the reasons as to why he acted as he did. It seems that the creature was acting against an internal struggle--one in which he wanted to be loved and one in which he wanted to be hated.
The following passage describes his internal conflict.
I recollected my threat and resolved that it should be accomplished. I knew that I was preparing for myself a deadly torture; but I was the slave, not the master, of an impulse which I detested, yet could not disobey. Yet when she died!—nay, then I was not miserable. I had cast off all feeling, subdued all anguish, to riot in the excess of my despair. Evil thenceforth became my good. Urged thus far, I had no choice but to adapt my nature to an element which I had willingly chosen. The completion of my demoniacal design became an insatiable passion. And now it is ended; there is my last victim!”
In the end, the creature is stating that his murderous rampage has ended. With the death of Victor, the creature has no reason to continue on with life. The conflict with Victor seems to be what allowed the creature to survive. His hope that Victor would come to accept him, eventually, was what forced the creature to keep living.
The entire speech by the creature was to ask Victor for his forgiveness, something Victor cannot do given he has died. The speech is meant to (or try to) allow the reader to find sympathy for the creature. The creature, in his speech, is simply trying to explain his actions and find comfort in Victor's forgiveness.
Chapter 24 of Frankenstein reminds a reader of Michaelangelo's painting in the Sistine Chapel in which God and Adam reach out to touch each other. There is a certain connection between Creator and creature as expressed by the great painter. Likewise, the creature, the child of Victor Frankenstein, opens his eyes, smiles, and desires love and to touch his creator; however, when he is totally rejected, the creature channels his emotion into revenge. But, if Victor were only to demonstrate any love for him, the creature would desist; for, in a bizarre way, the acts of revenge are a cry for attention, and, thus, love.
After Victor dies, the creature realizes the destructiveness of his love/hate acts: "in his murder my crimes are consummated." He admits to "a frightful selfishness" that hurries him to his heinous acts. Cognizant that his hateful acts have always been a cry for Victor's love, the creature asks Walton,
"Think you that the gorans of Clerval were music to my ears?" My heart was fashioned to be susceptible of love and sympathy; and when wrenched by misery to vice and hatred it did not endure the violence of the change without torture such as you cannot even imagine."
The creature abhors himself, as with the death of his creator, he becomes so terribly aware of the "impotent envy" that has propelled him to embrace evil as his good:
"The completion of my demonical design became an insatiable passion. and now it is ended; there is my last victim!"
Here is Shelley's message that, as Friar Laurence of Shakespeare's Romeo and Juliet has cautioned, "Virtue itself turns vice, being misapplied."