The identity between essence and the individual as a key question for the knowledge of nature in Aristotle's philosophy

Essence seems to be the substance but in a way different from that in which the individual is said to be a substance. Then, in what sense can essence and the individual be a substance? The question is relevant because both must be real. But is the identity between essence and the individual possible? And if it is possible, will the identity be total or partial? Faced with these questions it is necessary to consider that in Aristotle the study of the essence only makes sense while trying to explain the being of reality. Thus essence should be substance. From this consideration another question comes in: Is reality composed of two substances? or, how is it that both of them occur in the individual?