Maybe a mysterious Pokémon ranger and a shiny Pokémon like a Sylveon. The ranger is known for his ability to communicate with Pokémon on a deeper level. He saves the Sylveon from a dangerous situation, and from that moment, a strong connection forms between them. In the 'pokemon holy matrimony fanfiction', their story of love and connection could be the main plot.
Ash and Pikachu could be interesting main characters in this kind of fanfiction. Ash has such a deep bond with Pikachu that it could be imagined as a special kind of relationship leading to a holy matrimony in a very symbolic way.
One idea could be a Pokémon trainer and a Pokémon falling in love in a magical way. For example, a Gardevoir might develop deep feelings for its trainer through years of battling and traveling together. Another could be two Pokémon from different species getting married in a Pokémon - themed ceremony, like a Pikachu and an Eevee uniting their families.
A young and ambitious Pokemon trainer who wants to save their injured Pokemon through surgery could be a main character. Also, the Pokemon doctor who is an expert in performing these surgeries.
A new trainer and a legendary Pokemon. Imagine a young trainer who accidentally cuffs themselves to a powerful and mysterious legendary Pokemon. The trainer has to figure out how to communicate with the Pokemon and gain its trust while they are literally bound together. This would be a great opportunity for character growth for both the trainer and the Pokemon.
I think Misty from the Pokemon world could be a main character in this fanfiction. Since she has a connection with water - type Pokemon, she could easily fit into the underwater world of The Little Mermaid. Along with her, a Psyduck would be there. Psyduck's clumsy yet powerful abilities could add an interesting element to the story. And of course, Ariel would be a main character. She could learn a lot from Misty about the Pokemon world and they could team up to protect both their worlds from any threats.
A determined young trainer could be the main character. They have a special bond with Pokémon and are drawn to the mystery of the Sacred Fire. Their goal could be to learn more about it and protect it if necessary.
The main character could be a person who was once a part of an evil organization but has had a change of heart. In the 'pokemon next generation fanfiction', they use their knowledge of the organization's ways to protect the new generation of Pokemon. They start with a single Pokemon that they rescued from the organization and build a team as they go, facing challenges from their former comrades and also making new friends among other trainers.
Ash and Gary could be great main characters. They have a long - standing rivalry. If they were handcuffed together, it would be really interesting to see how they interact. Their different Pokémon - training styles would either clash or, over time, complement each other.
The main characters could be popular pokemon girls like Misty. Since she's feisty and determined, her being involved in a hypno - related story could be really interesting. Another could be Serena, as she's always evolving in her journey and a hypno situation could be a new twist for her character development.
Ash and Gary could be great main characters for this type of fanfiction. They have a long - standing rivalry and often face difficult choices. In a double dilemma situation, they could be competing for two different Pokemon, and their different approaches to the situation would make for an interesting story. Ash might be more focused on the bond with the Pokemon, while Gary could be more interested in the Pokemon's power.
A young and curious Pokemon trainer would be a great main character. This trainer could be someone who is always on the lookout for rare and unique Pokemon. When they encounter the worm - like Pokemon, they are immediately intrigued and decide to make it a part of their team.