Natsu could be angry at first. He's a passionate character, and being betrayed by those he considered family would make him want to lash out. But then, he might start to question what he did wrong and try to find a way to prove his innocence. He would probably be very determined to clear his name and get back the trust of his friends in Fairy Tail.
He might initially be shocked and confused. Natsu has always been so loyal to Fairy Tail, so this would be a huge blow to him.
At the start, Natsu would likely be in disbelief. He would try to talk to his friends in the guild, thinking it's all a big mistake. When he realizes that they truly believe he's betrayed them, he might become heartbroken. However, Natsu is also a fighter. He would use this pain as motivation to find out the truth behind the betrayal. He would not sit idly by but would actively seek answers, whether it's by investigating on his own or finding unlikely allies. He might also have moments of self - doubt, but his love for Fairy Tail would keep him from giving up completely on getting back to the way things were.
She might become angry at first. Natsu is known for her fiery temper. So, she could lash out at the person who betrayed her, confronting them directly and demanding an explanation.
Natsu would likely be extremely hurt. He has always been loyal to Fairy Tail, so being betrayed would be a huge blow. He might initially be in disbelief, not wanting to accept that his friends and guildmates could turn on him.
At first, they might be in disbelief. The members of Fairy Tail see Natsu as a core part of the guild, so it would be hard for them to accept that he has betrayed them. They would probably try to talk to him and find out what's going on. Some members might be angry immediately, thinking that he has turned his back on their family. But others, like Lucy, might be more hesitant to believe it and would look for a way to resolve the situation without conflict.
Natsu would be heartbroken. Fairy Tail is like his family. He'd probably go on a solo journey to clear his name and prove his loyalty. Erza would be stoic but deeply hurt. She'd start an investigation within the guild, using her influence and intelligence to uncover the truth. She might also isolate herself a bit while she figures things out.
He might initially be in disbelief. Natsu is used to the loyalty among his Fairy Tail comrades, so betrayal would be a shock to him.
The guild would likely be shocked at first. They consider Natsu as one of their own, so his attack would be completely unexpected. Some members might try to talk him down, like Lucy. She has a close bond with Natsu and would probably try to reason with him.
Gray would be shocked at first. He and Natsu have a long - standing rivalry - but also a deep friendship. He might initially be angry that Natsu would just leave like that, but then he would realize how much he'll miss him. He might also feel a sense of loss for the guild as a whole, since Natsu is such an important part of it.
If Natsu is a girl in this fanfiction, her character might change in terms of her relationships. For instance, she may be more self - conscious about her appearance compared to when she was male. Also, her interactions with male characters like Gray could shift. Instead of their typical rival - like banter, there could be a more complex emotional undertone, like a friendly - rivalry with a hint of romantic tension perhaps.
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.
In many fanfictions, Natsu protects Lucy by using his powerful fire magic against their enemies. For example, if they encounter a dark guild attacking Lucy, Natsu would jump in front of her and unleash a flurry of fire attacks like his 'Fire Dragon's Roar' to drive the enemies away.