Why is it always like this- like they're happy in the cutscene but they're just violent in-game (looking at you Jumanji: Welcome to the Jungle the game thingy)
My first playthrough was like this, but my second and third characters never even learned the Dark Arts, as I felt they rob the game of almost all of its challenge.
That's a major problem with the game, that it plays out exactly the same no matter what you do with it. In better WRPGs, especially from Black Isle/Troika/Obsidian, your gameplay style and moral alignment have a big impact on how the story unfolds.