Hikaru's rendition of a painting, "St John the Baptist" by Leonardo da Vinci

Who is he?

Toward the end of his life, Leonardo decides to return to the Florentine motif of using the festaiuolo. According to Michael Baxandall, a festaiuolo is a choric figure who introduce the play and remained on the stage while the paly is going on acting as a mediator who may point to what is essential and/or central on the stage. ("Painting and Experience in Fifteenth-Century Italy" Oxford University Press, 1972,  p71-73 )
Usually, the choric, angelic festaiuolo is pointing towards something and /or someone which clearly exists; however, we are not certain of what this being is pointing towards. Is it the Heaven? Dark void?
We also do not know the identity of this being.

He appears androgynous. Man and a woman in one. ...an original Adam before the separation/creation of Eve? Or is he an Angel?
Generally, this painting is known as Saint John the Baptist, but the cross and the animal skin, according to some of the experts, seem to be added later. If we mentally strip these "extra" elements, we are left with the few clues to the identity of this being.

A festaiuolo can be an angel or a human, so he can be St. John the Baptist.
We know that Christian tradition equates St. John the Baptist as Elijah like forerunner of Christ. By quoting the Old Testament (Tanakh), the New Testament Gospels equates St. John as the messenger who is sent before Christ/Moshiah(Messiah).
It is interesting to know that the word for an "angel" in either Hebrew (  מלאך ), Aramaic ( ܡܠܐܟܐ   ), or Greek ( αγγελον )also has a meaning, a "messenger".

The being in this painting seems to be pointing towards the point of origin. Is it the Garden of Eden where we may have fallen?
Or, one can see it as where we were born/created (a womb like place)
.. and perhaps the place we do return after death.

Perhaps this is a youthful angel of death imagined by Leonardo to take him to the world after life. It was towards the end of his life when he began painting this image and supposedly have brought it over the Alps to France.
This being is putting his left hand on his heart as if to swear that he is there to show Leonardo the way back(?)without deception and to take him on his last adventure/journey 'home.' This youthful being with the gentle gesture and a bit mischievous smile may be the combination of his beloved Melzi, and Salai. It may also be that this being is Leonardo himself in his youth, since the being is placing his "left" hand on his chest, not just showing the gesture to swear, but to remind us that it is "he," Leonardo, who had painted and created this picture, an inner self, who is the reflection of  "Imago Dei"...   {The painting at the top of this blog is my rendition of Leonardo's "Saint John the Baptist," and I have titled it as "Angelos" (angel/messenger) © Hikaru Hirata - Miyakawa}