I have never encountered a game that retroactively changes a companion's personality based on how you act. Why do you think that's the case in this game? Frankly it's a cop-out on what Larian themselves has said. If his personality and nature changes retroactively based on how you play then your character is not really influencing him. He's always been the way he is and in-universe you have no impact on it. Your character's choices don't actually matter, they don't change him really.
Exactly! This is what I mean when I say each of these companions has a 'default' alignment, which is based on the character's story when first we encounter them. It's something Larian's writers have established by way of having written these characters. What we as players do with these characters through the course of our games is an entirely separate issue.
And Gale's default orientation is a narcissistic megalomaniac (which does not conform with being good), for how else can one describe a character who declared himself the greatest wizard ever and then tried to usurp the powers of a god?
