Hyde is represented as a deformed man, but his deformity is more ethical than physical, because he has a total lack of moral principles.

He is best described as Jekyll-deformed, a parody of a man who cannot survive in this society. In fact, he takes refuge in Jekyll's body, because he needs Jekyll in order to hold up. To know Jekyll's full personality, it is necessary to first know Hyde and vice versa.

Firstly, Jekyll is presented as the good one and Hyde as the evil one, but later on, it is not so clear. Jekyll is "bad" because he does not want to admit he is Hyde. Although he feels sorry for Hyde's actions, he acts as if Hyde was another person, when he is nobody else but himself. And Hyde is not so "bad" because he is just natural, he has not been educated with moral and social principles, he has been created by Jekyll without taking into account his education (he neglects his education as Victor Frankenstein does when he creates the creature).

Jekyll is "the source of all evilness" because of his prudery.

Sigmund Freud's theories of Ego, Id and Superego can help us to understand this statement:

Jekyll is the EGO, the conscious part of himself; he is rational and dominated by the social principles and by a strong morality.

Hyde is the ID, the unconscious part of Jekyll, he is natural and impulsive (not rational), and, therefore, he does not know any social neither moral norm to follow.

The SUPEREGO are the religion, society, ethics, moral, &c. represented by Lanyon and Utterson. This rules are the ones that keep ID under control, except for when we are sleeping (normally at night). And that's why Hyde acts throughout the night, because the SUPEREGO and the EGO cannot control him.

Hyde is a metaphor of uncontrolled appetite (he is the ID), and, therefore he is AMORAL (not immoral, this would mean he does not obey a moral he has, but amoral means that he has NO moral at all).

Hyde, as social identity, can be seen as the internal side of Jekyll (we have seen why) but he can also be seen as a political and economic man. Hyde represents the Victorian man who cannot bear confining himself beneath the domestic covers, who has to "live the life".