How would the other characters in 'Hetalia Prussia turns into a girl fanfiction' react?

Well, one possible plot could be that Prussia, now as a girl, has to navigate the world of international relations in a different way. Maybe other countries would react with shock at first and then gradually get used to this new Prussia. She might also have to deal with new emotions and how to present herself in a more feminine way while still maintaining her Prussian pride.

Tails would probably be very curious and eager to figure out how to change Sonic back. He might study Sonic's new form scientifically. Knuckles, on the other hand, would be a bit more confused but still stand by Sonic's side. Amy might be initially jealous because she's used to being the main female around Sonic, but then she could become a great friend and help Sonic adjust. Dr. Eggman would likely see this as an opportunity to take advantage of Sonic's confusion in her new form.

Jiraiya would have a very interesting reaction. Since he's a bit of a pervert in the series, he would have to really adjust his behavior. He might also see this as an opportunity to study the differences in chakra and fighting styles between male and female ninjas while also trying to guide Naruto in this new form.

Some characters might be very shocked at first. For example, Sandstorm, if she was in a relationship with Firestar before, would be confused and have to re - evaluate her feelings. But others, like Graystripe, might be more accepting and just see it as another change that they have to adapt to. Younger cats in the clan would probably be more curious and excited about this new Firestar.

Rukia would probably be one of the first to be both shocked and amused. She might tease Ichigo a bit at first but then quickly get serious about helping him. Chad would be very accepting and offer his protection as usual. Uryu might be a bit more skeptical at first, thinking it's some kind of new Hollow trick. Orihime would be very empathetic and try to make Ichigo feel comfortable in his new form, maybe even offer to make some new clothes for him to fit his new body.

The other characters' reactions would be quite diverse. For the more competitive male players, they might see this as an advantage or a disadvantage depending on their relationship with Kirito. If they were rivals, they might think it's a chance to outdo him now that he's a girl. But if they were friends, they would offer support. Female characters like Silica might be excited to have another girl around and might start sharing girl - only things with Kirito. The guild members of Kirito's previous guilds would likely be confused but still accept him, after all, they know it's still Kirito inside.

Among the Nordic countries, if Canada turns into a girl, they might treat her with more chivalry. Finland could be really friendly and share some of his own experiences with dealing with a different kind of identity. Sweden might be a bit quieter but still show his support in his own way. Norway could be a bit more standoffish at first but then come to accept her new self as part of the group.

Nagisa's best friend might be really surprised at first. But then, being a true friend, would support Nagisa through this strange change. They would probably help Nagisa with things like choosing girl - appropriate clothes or dealing with any mean comments from other students.

Riku would probably be really confused at first. He might act a bit awkward around Sora, not sure how to treat this new female version of his friend. Kairi, on the other hand, could be more empathetic. She would likely help Sora adjust to being a girl, like teaching her about makeup or different hairstyles if that's relevant in the story's world.

The other gumballs in the gumball machine might be very confused. They've never seen such a thing happen before. Some might be scared and think it's some sort of curse. The humans who find the girl - gumball could be initially shocked. But some kind - hearted ones might take her in and try to help her adjust. If there are any pets in the story, they might sniff her curiously, not really understanding what she is but sensing that she's different.