At one point I tried to put together some thoughts on this.
It's easy to be confused about it IMO because the blackness was foreshadowed earlier in WGW several times in Covenant's dreams.
But I'd like to say that we cannot be sure if the blackness
is the wild magic, or if Covenant is expressing power with more than just wild magic. If the wild magic is altered, or if Covenant now has another source of power.
In 'WGW Ch 9, March To Crisis' was wrote:What does the blackening of the wild magic truly signify?
This is much more complicated than it first appears.
The simplest theory is that the venom is getting stronger. And that Covenant is now racing against the clock to save the Land before he succumbs to the venom.
But when did the venom get that power? It is a moral poison, making Covenant apt to power as well as increasing his desire for it. Now it's going far beyond that. It's not merely doing what it has done all along, but more so - it is doing something entirely different.
Is it changing wild magic itself? I have to say, no. Wild magic is unassailable, or else the last six books were needless.
I think it's fairer to say that Covenant's expression of power is being changed. It's no longer pure; it's succombing to darkness. Or maybe Covenant is displaying a new power now - something other than wild magic.
But now consider Covenant's confrontation with the bees. For the first time, he's thwarted the raver's attack on his own, displaying awe-inspiring control of the wild magic. Whatever it is that is changing in Covenant, it is making this possible as well. Life and Death, intimately interwoven ...
Then back up and consider the apparent source of the blackness. It was not explicitely evident until Covenant grasped the endangered krill. Reading this, it appears that the blackness lept from the krill straight into Covenant! Remember, too, that Gibbon is also a raver: was this another attack on Covenant after all - in order to strengthen the venom within?
Consider these lines, which occur before this indicent with the krill.
"His brain had gone black with venom. Come and get me!"
"Fire flashed in his mind, alternately white and black."
"They had all become one virulent vision, and in it his fire was as black as venom."
All of these hint at the corruption of the wild magic to come. Why would this be? Is the venom strengthening on its own?
So I am left with a lot of puzzle pieces that don't quite fit with each other. Here is the best theory I can make:
By defending the krill, Covenant opens himself to a new form of attack, which strengthens the venom within him. The venom is now power itself, capable of being weilded by Covenant's passion just as the wild magic is. And, in his poisoned passion, Covenant is now articulating both of them, equally, without distinction. "It is force nonetheless, fire capable of riving the heavens".
A good question would be: if Linden grasped the wild magic now, would it be white?
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