“Christ” is reference to the eternal oneness of God and man – this alone is the “Real Christ”.
Christ, then, is neither God nor man, but the eternal oneness of the two.
Some fathers explained the difference between “who” and “what” this way: Existence = “that” something is Essence = “what” it is that exits Person = “who” it is that exists.
The early fathers defined person as the agent of the soul, the subject, the I am, one’s self-identity or “who” one is – which is not “what” one is, but “who” one is. Thus everyone, responsible for their own choices and behaviors in life, is the person he becomes.