He's whatever you want him to be.
But it would also be wise to enquire to discover the author's intent.

The symbolism of art, is whatever a person interprets the symbolism to represent.
Bu then there's also what the artist wants to express through the symbolism.
But then there are artists who know what the symbolism means to them but they also know that the symbolism may mean something different to another.
In that some artists don't care if someone interprets their work differently from what it means to them.
Another's interpretation has no affect on their own connection to the art piece.

Like K-Pax.
Is he an alien or a crazy person?
This was the dilemma i faced after watching it the first time.
I have since seen an entirely different answer to these questions since watching it again.

I interpret Powder as a human who had a major transformation.
And yes, heart touching for me because it symbolized transformation and the infinite potential of the human being.

He is also Jesus like in his human journey.
An extra ordinary human, far above the capabilities of others.
Loved by some, hated by others.
But in the end he transcends the human form.

A mordern myth story in the same vane as Jesus and other spiritual heros of the past.