Adaptational Jerkass

Regardless of the medium, characters are introduced and established as having certain traits and, as such, the fans of those works expect those characters to adhere to them. If they're The Hero's trusted friend in the novel, the film adaptation should convey that as well, but wait — why is the hero's trusted friend from the novel, suddenly giving him the cold shoulder in the motion picture? Why is the faithful Love Interest from the manga two-timing him in the anime? And the Lovable Rogue, who gives to the poor in the television series, only cares about lining his own pockets in the Made-for-TV Movie. They weren't like that before, so what happened? The answer is: the character has suffered from Adaptational Jerkassery, the narrative equivalent of Taking a Level in Jerkass. Whatever the reasons, the writer(s) has seen fit to change the character's original positive portrayal, to make them more of a jerk. Perhaps the character was a Jerk with a Heart of Gold in the original work, but the adaptation failed to convey the "heart of gold" aspect. Thus, turning them into a total jerk. Or it could be due the adaptation being Darker and Edgier than the original, and the character's portrayal was changed accordingly. However, while there may be some overlap with Adaptational Villainy, the key difference here is, the character isn't necessarily villainous. In many cases, they're still on the good side and due to Adaptational Angst Upgrade, can be a comedic sociopath, an Anti-Hero or just The Friend Nobody Likes. Because of the nature of the trope, it's obviously related to Took a Level in Jerkass and by extension contrasts with Took a Level in Kindness. A subtrope of Adaptation Personality Change. Its inverse is Adaptational Nice Guy.