What does the creature vow to do at the end of the novel?

At the conclusion of the novel, the creature vows to die. 

"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 that I shall be slow to perform this sacrifice. I shall quit your vessel on the ice raft which brought me thither and shall seek the most northern extremity of the globe; I shall collect my funeral pile and consume to ashes this miserable frame, that its remains may afford no light to any curious and unhallowed wretch who would create such another as I have been. I shall die.