He might be angry at first. Natsu is a passionate character, so he would likely feel betrayed and lash out immediately.
Lucy might be heartbroken. After all, Team Natsu was like a family to her. She could initially go into a state of shock and disbelief. Maybe she would try to plead with the team to let her back in, explaining that whatever they thought she did was a misunderstanding.
Maybe he violated some important team rules. For example, he might have gone against the orders of the team leader during a crucial mission.
On the other hand, she could see it as an opportunity for a new start. She might gather her strength and decide to prove herself outside of the pack, or she could try to find a new group or community where she would be more accepted.
He might be really angry at first. He's given so much to the camp, and being kicked out like that without a proper explanation would make him furious. He could storm off, vowing to find out the truth and clear his name.
He might be really angry at first. Natsu is a passionate character, and being kicked out unjustly would make him furious. He could storm off vowing to prove his worth and show the guild they made a mistake.
Batman could become more of an anti - hero. He might start working against the Justice League's interests, thinking that they have wronged him. He would use his skills and resources to expose any flaws in the League's operations and undermine their public image.
Naruto might initially be shocked and hurt. After all, being expelled by his own family is a huge blow. But being 'godlike', he could quickly turn that pain into determination. He might decide to prove his worth and show his family that they made a big mistake.
Natsu would probably be very angry at first. He loves Fairy Tail like a family, so being kicked out would feel like a huge betrayal. He might go on a rampage, shouting and arguing with the guild members who made the decision.
Natsu might be initially shocked and confused. He's not the type to expect rejection, so he could be at a loss for words at first. For instance, he might just stand there with his mouth open, not believing what he just heard.
Well, in many fanfictions, Natsu might initially be in shock. He's a passionate character, so he could react with anger. He might lash out at Lisanna or the person she cheated with. He could also go into a state of self - doubt, wondering what he did wrong.