A Character With Character

I like alternate history. Stories that tell a 'what if?' have a strong appeal to me. It's a great way to analyze what could have been, but to also better understand the why and how things happened the way they did.

When writing alternative history, or counterfactuals in the parlance of the subgenre, there are certain difficulties when it comes to writing an established character. Whether you are writing Marvel Comics' What If? a story about Spiderman, or writing an opus about the extended life of General Custer had he not succumbed at Little Big Horn, it seems imperative that you DO NOT change the character of that person. In other words, using a bad analogy, characters in What If stories are akin to subjects of a hypnotist. You can have them cluck like a chicken onstage, but you cannot have them do something that they would not otherwise be predisposed to do.

So, how to reconcile character growth of a historical character? People naturally change over time. People can change who they are. It is necessary for a character to arc, to change from point a to b. But it seems wrong to write that General Custer, learning to curb his impulsive-self after barely surviving the ambush, then lived a life of solemnity to a ripe old age.

It goes against his character.

What do you think?