In a fanfiction, Serena as a mermaid might be part of a mermaid kingdom that has a long - standing feud with a group of sea - dwelling Pokemon. Serena, being kind - hearted, tries to bridge the gap between the two sides. She uses her charm and the skills she has learned in the Pokemon world to negotiate peace, all while looking stunning with her mermaid tail and long flowing hair.
The plot might start with Serena finding a strange, enchanted shell on the beach. When she touches it, she is turned into a mermaid. In this new form, she realizes she can communicate with water - type Pokemon in a different way. She embarks on a journey to find the origin of the shell and the power that transformed her. Along the journey, she makes new friends among the mermaids and Pokemon, and together they face a powerful villain who wants to use the shell's power to take over both the sea and the land.
One way to find good Pokemon Serena Mermaid fanfiction is to search for it on Tumblr. There are often communities dedicated to sharing and discussing such fan works. A lot of these fanfictions might incorporate elements of Serena's journey in the Pokemon series, like her contests, but with the added twist of her being a mermaid. It could be really interesting to see how her mermaid abilities interact with her Pokemon skills.
Love and relationships are also quite common. Whether it's her relationship with Ash in a new light because of her mermaid form, or new friendships she forms with other water - type Pokemon. In some fanfictions, there's a theme of acceptance. Serena has to deal with how others will accept her as a mermaid, especially those who are close to her like her friends and family in the Pokemon world.
One idea could be that Serena is initially deceived by Team Flare's false promises of a better world for Pokemon. She might see their flashy technology and think they can help her become a stronger trainer. But as she gets deeper into the team, she starts to realize their true, evil intentions, like stealing Pokemon for their own gain.
A plot idea could be that Serena discovers she's pregnant during a big Pokemon tournament. She has to decide whether to continue competing or focus on her pregnancy. Another idea is that she finds a rare Pokemon egg that has some sort of magical connection to her unborn child. Or perhaps a villain in the story tries to use her pregnancy to their advantage, thinking she'll be more vulnerable.
Perhaps in the fanfiction, Ariel and Eric get married and have to deal with the cultural differences between the underwater world and the human world. For example, Ariel has to learn the proper etiquette in Eric's kingdom while Eric tries to understand the unique traditions of Ariel's mermaid family.
One idea could be a Pokemon that has the ability to transform into a mermaid and it goes on a journey to find its true origin. It could face challenges like being hunted by humans who want to study its unique form.
One interesting plot idea could be Serena and Calem getting lost in an uncharted region of the Pokemon world while on a research expedition. They have to rely on their Pokemon and each other to survive and find their way back. Another could be a story where they compete in a special, high - stakes Pokemon tournament that tests not only their battling skills but also their friendship. And perhaps a plot where they discover a new type of Pokemon together and have to protect it from an evil organization that wants to use it for its own gain.
One idea could be that Serena's 'cheating' might be a misunderstanding. Maybe she was seen with another trainer in a compromising position, but in reality, they were just discussing a very important Pokemon training technique that Ash didn't know about at the time.
One idea could be that Marinette (from Miraculous Ladybug) discovers a magical seashell that transports her to the underwater world of The Little Mermaid. There, she meets Ariel and they team up to fight an underwater villain who is stealing the magic of both the surface and the seabed. Maybe the villain is after the Miraculous and Ariel's voice for some dark purpose.