[@ViannaNight][@NobodiesHero]

Y'know this whole 'Sun and Moon' thing is... covered by Light and Dark elements... This is all pretty unnecessary.

You might be reading into representations a little too far and coming up with concepts that seem very out of place. We're looking for elements not Astrological phenomena.

Spirit is related to the body and soul. The opposite to that is Death. Simple enough? However, since death is not a "good good", think of something else maybe.