Altair will probably become more reclusive. He doesn't like dealing with people, much less monsters that could eat him if they wanted to. He might reluctantly try to get to know some people. If he was going to be stuck in Ryslig he needed allies and information. He's going to hate the Fog God. She's very similar to someone from his world who also forced a "gift" onto him. It's going to be interesting to see how he deals with having to eat people. He's not going to accept it. He promised that he wouldn't kill ever again and he has no intention of breaking that promise.

Arrakis won't be very reclusive at all. He never liked being alone and he will definitely not want to be alone now. He has very few memories and none of them are very pleasant. The world he came from wasn't a nice one. If anything he will probably throw himself into making friends and helping others so he doesn't have to think about it. He will probably hate having to eat people but he will very reluctantly do it if it means less people would be hurt.