Who is speaking, "I am malicious because I am miserable" from the book Frankenstein?

The monster is speaking in the phrase provided above. The entire quote is as follows;

"You are in the wrong," replied the fiend; "and instead of threatening, I am content to reason with you. I am malicious because I am miserable. Am I not shunned and hated by all mankind? You, my creator, would tear me to pieces and triumph; remember that, and tell me why I should pity man more than he pities me? You would not call it murder if you could precipitate me into one of those ice-rifts and destroy my frame, the work of your own hands. Shall I respect man when he condemns me? Let him live with me in the interchange of kindness, and instead of injury I would bestow every benefit upon him with tears of gratitude at his acceptance. But that cannot be; the human senses are insurmountable barriers to our union. Yet mine shall not be the submission of abject slavery. I will revenge my injuries; if I cannot inspire love, I will cause fear, and chiefly towards you my arch-enemy, because my creator, do I swear inextinguishable hatred. Have a care; I will work at your destruction, nor finish until I desolate your heart, so that you shall curse the hour of your birth."