Superego, Id, Ego

The superego could be represented by the creature. He is holding Victor responsible for his actions; he created the monster and therefore should have taken care of him. The creature punishes Victor for backing away from his responsibility.

The id would then (to me) be best represented by Victor. He acted upon impulse by creating the monster without thinking of the many possible outcomes. He just thought of the recognition he would receive and began working tirelessly on the monster until his completion.

The ego would be represented by Henry Clerval. He brings Victor back to reality and helps nurse Victor back to his normal state of mind. He keeps Victor in good balance and draws him away from danger (takes him away from the sciences and all that remind him of it to keep him from lapsing back into his insanity).