When I was a kid, I defined the good guys of a story as the one who kills the bad guy. So it's interesting to me (probably not to anyone else) how few of the villains in Narnia are killed by the main character.
Aslan kills the Witch in LWW, not Edmund or Lucy. Glozelle and Sopespian kill Miraz in PC, not Peter. (Peter does kill Glozelle but he's in such a small role that I don't think of him as the villain of the book.) I guess you could argue that Rilian, who kills the LOTGK, is one of the main characters of SC but I don't think of him that way. The closest thing to a main hero defeats main villain scene in the books is when Tirian throws Shift into the stable in LB, and then it's Tash who finishes him off.
You kind of sense that the screenwriters for the Narnia movies were frustrated by this. (I'm sorry for bringing movies into Talk About Narnia. But I feel like it demonstrates what I'm talking about.) They didn't seem to want to outright change who killed the bad guys in any of the stories but that seems to have been because they didn't want to anger fans. While Aslan ultimately kills the Witch in the LWW movie, Edmund "kills" her in both the PC and VDT movies. You get the impression the writers thought that would been a better ending than the canonical one.
For better or worse-for who knows what may unfold from a chrysalis?-hope was left behind.
-The God Beneath the Sea by Leon Garfield & Edward Blishen
Interesting point, Col Klink.
In a lot of media, the good guy killing off the bad guy is the big, exciting struggle at the end story — for instance, IIRC, most Disney animated features are like this. Thinking about Narnia, though, Lewis often seems to give a lot more attention to moments of joy rather than the comeuppance of darkness — the statues coming back to life in LWW, the Romp in PC, et cetera. Even in the battles of wits and steel with the Green Witch in SC, it's Puddleglum's speech that stands out as the Big Moment, not the struggle with the serpent afterwards. I think almost everyone thinks of Puddleglum as the hero in that chapter, whereas actually killing the serpent is a messy, chaotic team effort instead of an epic battle.
I guess I would say that in his books, Lewis did not seem primarily focused with the defeat of evil, and his main characters having the glory of its defeat, but with going further up and further in, seeking Joy. Defeating evil was a necessary step in doing that, but it wasn't the point of the story, if that makes sense — and therefore the identity of who slayed the villains wasn't as big of a deal. A J.R.R. Tolkien quote comes to mind: "I do not love the bright sword for its sharpness, nor the arrow for its swiftness, nor the warrior for his glory. I love only that which they defend." I hope any future writers of Narnia adaptations will appreciate this tendency of Lewis's storytelling!