Must a Creator Immortal?

In the previous post, I asked why the White Witch thought she could kill Aslan. She knew that he created Narnia (and presumably the universe of Narnia) so how could she not realize that he is immortal? 

Before we get to an answer we should note that a spirtual mistake of this sort happen another time in Narnia. The Narnians assumed that Tash was simply a false god, one that did not exsit. And they weren't the only ones: the Calormen of "The Last Battle" also did not believe in the existence of Tash and I think we can argue that the Tisrocs did not either. Remember this exchange: 

    "O impeccable Tisroc," said the Vizier. "In comparison with you I love neither the Prince nor my own        life nor bread nor water nor the light of the sun."

    "Your sentiments," said the Tisroc, "are elevated and correct. I also love none of these things in                   comparison with the glory and strength of my throne..."

The Tisroc mentions no love for Tash only for his own power. Strangely enough, the only character we know for sure believed in Tash was Emeth!  

As for the Narnians, only when Tash came into Narnia did they realize there was a spiritual evil that had possessed the Calormens and aimed to fight against Aslan on Narnian soil. 

Be that as it may, I think there's a reason the White Witch did not equate Creator to immortal, because she did not equate Destroyer to immortal. She was the great destroyer of Charn, yet not immortal. What is the difference between creation and destruction. In fact, destroying is far easier than creating. Only a truly intelligent and loving being can create, but any tyrant can destroy. 

The value of creation is underestimated, undervalued, and perhaps even vilified. Screwtape says, "At present the Enemy says 'Mine' of everything on the pedantic, legalistic ground that He made it: Our Father hopes in the end to say 'Mine' of all things on the more realistic and dynamic ground of conquest." Thus, the devil, the White Witch, Tash, the Tisroc, and so many others gain power and ownership through destruction. But in truth, only evil must be destroyed, ownership is attained via creation. And a true creator must be greater than what he creates. Thus, the creator of the world must be immortal.