Traditional writing books will tell you that your characters must grow and change over the course of a novel.
I think these are talking about Literary novels. The writing books I’ve read that say this are definitely geared towards more Literary novels.
However, I once read in a book on writing genre fiction, especially a series, that characters shouldn’t change.
I think there’s merit in this, because a character changing 20 times from novel to novel would just get tiring. Further, I know genre readers who like things the same way for a good while. How long depends on the reader, or viewer, or player, but most of the people I know who are fans of a genre series, be it book, show, game etc, tend to want the same characters in a vast array of scenarios.
I’m going to cite a few series’ close to my heart.
R A Salvatore’s Drizzt novels – there’s like 30 of them now – seem to have the main character remain the same, or mostly the same, since the 70s. He’s explored darker and more complex moral thinking of late, to be sure, but I think that’s mainly because he’s written 30 books with the same main character. Eventually, sure, Drizzt has to change. It’s inevitable. But when he changes it’s either gradually over several books or because of traumatic experience.
Harry Dresden, of Jim Butcher’s Dresden Files, stays mostly the same. There might be leeway, sure, but mostly? He’s still the gentlemanly, badass, charming, sincere, bookish wizard PI he’s been since book 1. Changes, as you’d expect, is a book wherein in he does something evil, or at least not good. I won’t tell you what, go read it for yourself, but it’s a new chapter in his progression as a person. But the change in Changes is fairly small in the big picture. He’s been pretty much the same level of awesome for 16 books. What changes is the scale of the threats he faces – The Dresden Files is all about escalation, and Butcher does that EXTREMELY well.
Then there’s Harry Potter. He gets darker and angrier, and guys have responded well to that. You’d change over seven books too if everyone you love and care for gets killed by your nemesis (spoiler alert). I heard that, originally, Harry was going to die, but Rowling got death threats, so she caved. I think Harry’s mood changed, but fundamentally, he didn’t. Then again it’s been decades since I read the books, so my info might be a little unreliable at this time.
So there’s some arguments for stasis, at least in the short term. Do you have any examples to add?