How did the creature feel after killing William and framing Justine, and what does he tell Frankenstein about the locket?
Immediately after killing William, the creation is filled with a sense of joy and power. He realizes for the first time that he, too, has power. He has the power to inflict pain and misery on man, specifically Victor. He says, "...my enemy is not invulnerable; this death will carry despair to him, and a thousand other miseries shall torment and destroy him."
The creation tells Victor how he used the miniature portrait to frame Justine (by placing the portrait in one of the folds of her dress) because of his rage from realizing that no woman would ever look on him softly and with tender feelings because of his appearance. He chooses to punish Justine symbolically for all women. "...but she, shall suffer; the murder I have commited because I am forever robbed of all that she could give me, she shall atone."