What’s up with the Shadow in A Wizard of Earthsea? (Caution, post is one big spoiler.)

I keep trying to write a grand scale blog post about Ursula K. Le Guin’s metaphysics of evil in the Earthsea cycle. Unfortunately, there seems to be an unmanageable number of lose ends that must be tied before I can construct an accurate depiction of Le Guine's moral framework. Instead, I will focus on a single loose end, and see what happens.

What’s up with the Shadow in A Wizard of Earthsea?

The central plot of WOE is as follows: Ged, a powerful wizard in his proud youth, unleashes a shadow from the realm of the dead (cue Sylvester McCoy: “That did not come from the land of the living”). Ged spends the rest of the book figuring out how to stop it. He meets with success when he pursues it rather than running from it. He finally defeats it by walking to meet it, clothed in radiant light. He embraces it and addresses it by its true name, which is also his own.

Ged reached out his hands, dropping his staff, and took hold of his shadow, of the black self that reached out to him. Light and darkness met, and joined, and were one. 

WoE page 201.

After defeating his foe in this manner, Ged gasps to his friend:

 “Look, it is done. It is over. [...] The wound is healed.” […] “I am whole, I am free.”

WoE page 202

These quotes suggest a philosophy in which good and evil are equally powerful forces within human nature, and that balance and wholeness comes when the individual finds a way to embrace (or perhaps integrate?) both natures within himself. It brings to mind ying and yang.

This was my initial interpretation, and it is consistent with other hints about the nature of evil sprinkled throughout the book. For example, early in WOE, one of Ged’s teachers cautions him:

“You must not change one thing, one pebble, one grain of sand, until you know what good and evil will follow on the act. The world is in balance, in Equilibrium. […] to light a candle is to cast a shadow.”

WoE page 56.

This suggests that a good act is but one side of a bad act, as does the following:

“Rain on Roke may be drought on Osskil.”

WoE page 68.

However, other events in the book did not seem consistent with this interpretation.

The Ying and Yang theory suggests that the Shadow which Ged unleashed is a personification of the evil half of Ged’s nature - a Mr. Hyde.  But the shadow spends the middle of the book behaving much like an independent force, something akin to a Christian demon. It is described as wanting to possess Ged:

 It would be on his track now, seeking to draw near to him, to take his strength into itself, and suck up his life, and clothe itself in his flesh

 (WoE 98)

 The following quote frames the puzzle perfectly. 

It [the shadow] was drawn to him and would try to work it will through him, being his creature.

WoE page 99

It seems odd for a creature to work its will through the maker. Usually the maker works his will through the creature. Is this shadow creature part of Ged, or something outside him wanting to get in? Do the evil actions of the shadow represent evil desires that Ged has? They appear to be the desires of a stronger force playing for much higher stakes, wanting to use Ged’s body and power as tools towards a larger purpose.

In the middle section of the book, Ged finds himself in a castle housing a stronger and older evil than his shadow. Ged is tempted to ally himself with this power, but he refuses. We are told:

It is very hard for evil to take hold of the un-consenting soul.

 WOE page 137

This makes it sound like evil is an external force, not an integral part man’s nature.

So then what does it mean when Ged defeats the Shadow with a hug and his name?