A mentor figure could be the one betraying the mc. The mc trusted this mentor completely, but the mentor has some hidden motives. Maybe they are working for a greater evil and see the mc as a threat or a tool to be used, so they betray the mc, which then causes the mc to turn dark.
The MC could become a penguin by accidentally entering a forbidden area or getting involved with绁炵 powers. Challenges? Well, there could be problems like not being able to move fast on land or struggling to fit in with the penguin community.
Well, often in such a 'ash gets betrayed fanfiction', the story might start with a seemingly normal day for Ash. Then, out of the blue, someone he trusts deeply, like Pikachu or one of his human friends, does something that he perceives as a betrayal. This could be something as simple as not believing in him during a crucial battle or siding with an enemy for a reason that's not clear to Ash at first. It can create a lot of emotional turmoil for Ash and make for a very engaging read.
At first, he's likely to be shocked. Issei is often portrayed as a character who trusts easily, so betrayal would come as a big surprise. He might not believe it at first and try to find reasons to justify the actions of the person who betrayed him.
One possible reason for Ash getting betrayed in the fanfiction could be misinformation. A villain might spread false rumors about Ash, making his friends believe he has done something wrong. His friends, without verifying the truth, turn against him. It's a sad situation where lack of communication and trust plays a big role.
Well, usually in such a manga, the girl is held against her will, maybe in a secluded place. There could be attempts to rescue her by friends or heroes, and lots of tension and drama along the way.
One possible plot could be that the main character (mc) is betrayed by a close friend or ally. This betrayal shatters their trust and makes them see the world in a different, darker light. They might then start to use more ruthless methods to achieve their goals, perhaps seeking revenge against those who wronged them.
At first, Naruto would be in disbelief. He has always trusted his friends wholeheartedly, so this would be a huge blow. He might then feel a deep sense of anger and sadness. However, Naruto being Naruto, he would likely also start to look for ways to prove his innocence or the misunderstanding. He might go on a journey of self - discovery to figure out what went wrong and how he can win back his friends' trust, all while dealing with the pain of the betrayal.
In the '4 kunoichi gets betrayed fanfic', it could be that the four kunoichi are working for a noble cause. However, one of their own, due to jealousy of the attention the others get, decides to betray them. She spreads false rumors about them, making the whole ninja community turn against them. The four kunoichi have to prove their innocence and also figure out a way to deal with the traitor within their group.