In chapter 17 of Frankenstein Victor eventually agrees to make a companion for the monster. At first, he abhors the idea, but the monster uses reason to wear him down. Claiming to be evil because he is hated by man, he says that a companion will remove the need for him to feel hatred toward man.
“What I ask of you is reasonable and moderate; I demand a creature of another sex, but as hideous as myself; the gratification is small, but it is all that I can receive, and it shall content me.”
He also plays upon Victor’s emotions, “Oh! My creator, make me happy; let me feel gratitude towards you for one benefit!” Although Victor reviles the monster, he is able to be moved to some degree by its misery and loneliness.
Finally, since the monster promises to flee forever from the “neighborhood of man” with his companion, Victor feels that it would safer to go ahead and give him what he wants, knowing that man cannot protect itself from his creation.