Ah... I had been meaning to do some fan-art of C.S. Lewis' 'Chronicles of Narnia' for some time...
I present to you one such submission.

Within said tales, there are many strange creatures abound. all of them seeming to coexist in the lovely world of Narnia. All save for a few 'outside' influences: The White Witch, and the Human Children (IE: Diggory and Polly, the Pevensie Children, Etc.) In all of the books, the human children are simply... well, human. Now, the Witch on the other hand...

In the first book, A human boy and girl (Diggory and Polly) make a venture to a Nexus of sorts by means of some magical rings forged by Diggory's slightly mad (Alchemist?)
Uncle/mad scientist. It is within the Nexus (Which is a world of grass tree's and small pools, each of which transport to another world.) that Diggory and Polly come across a decaying world with a dying sun. Upon further investigation, the children find a large stone castle, and within it, the last few seen survivors of an apparent all out war. It may have just been my imagination, (As it almost always is...) but I was given the faint Idea that, perhaps the Witch, (Janus...? I think that's her name.) Was simply a warlord of the time she was released from. Albeit, a magic wielding one, but a skilled warlord nonetheless.

Now, if my memory serves, (Its a coin flip these days...) Janus (If that IS her real name) brought with her a somewhat large dagger which appeared to be made of some type of stone. In the Book "The Lion the Witch and the Wardrobe" it is this blade (SPOILERS) that slays the all-but immortal resident deity of Narnia, Aslan.
The Knife appears some time later in one of the last books, and I believe I recall someone mentioning that the blade itself was a form of death, inflicting an end to whatever it happened to be used upon.

So... My lovely mind has come up with this design: An entropic dagger, wrenched from the far reaches of time and space by an insane Dictator, made of some type of anti-matter metal.

Yeah... That was my reaction too.

Welcoming all posts, and apologizing if I have somehow mixed up my Narnian facts.

~nyu~

-Theory