What's In Character?

This springs from a post I made recently and since the thread went a different way, I'd like to continue it here. My question was originally to @killemall and I'd still like him to respond because I think his input would be worth reading, but it's also just a general question that pertains to battles on CV as a whole. I don't really feel like writing more so I'll just start with the relevant bit of the original post:

Getting off on a tangent though, during Infinity, did Thanos use a force field, telepathy, telekinesis, independent teleportation, or matter manipulation at any point? How about in his recent origin story? I think there was something in Avengers Assemble with telepathy, but what was the extent and context of that and what about the others? When was the last time he used these abilities? Sometimes I wonder what goes into people's considerations for which behaviors are "in character" and which aren't. If a character used to do something "a lot" but doesn't anymore, could their character be said to have changed? Would that be an outlandish concept since we're pretending these characters are real people anyway? Or do people prefer to hold a static concept of these characters in mind even though their use through time and portrayals under many writers would almost require something far more fluid? If this fight should so happen to start, don't worry, I'll get out of your hair, but I felt like rummaging through some thoughts.

Thanos was being used in the original thread and I am curious about the answers to the questions I posted about that character specifically as well as the general topic. He might be a good character to use as an example of what's being discussed but I'm sure there are others too.