The player character is important, of course. Then there are the Gym Leaders in the Unova region. Also, N, the king of Team Plasma, is a very important character. His views on Pokemon liberation drive a lot of the story's conflict.
In Pokemon Black and White 2 story, the player character is central. Hugh is a prominent character with his own story arc related to his sister's stolen Purrloin. The various Gym Leaders like Roxie in Virbank City are also main characters in a sense as they are part of the journey. There are also characters from Team Plasma, such as the new leaders or members who drive parts of the story. They interact with the player and Hugh, creating different plot situations.
I'm not sure specifically as there's not much widespread knowledge about this story. But it could have a young trainer as a main character, similar to other Pokemon stories.
N is often a very popular character. His complex backstory and his connection to the Pokemon in a different way compared to other trainers make him a fascinating subject for fanfiction. Writers can explore his inner thoughts and his journey to understand the relationship between humans and Pokemon more deeply.
In Pokemon Black and White Story, the main character, a budding Pokemon trainer, is at the heart of the action. This trainer is on a quest to become a master. Then there's N. N is an interesting character as he has a very different perspective compared to most people in the Pokemon world. He believes that Pokemon should be free from humans, which is in contrast to what most trainers think. Additionally, characters like Professor Juniper also play a role. She provides the trainer with the starter Pokemon at the beginning of the adventure, and thus is also an important part of the story.
Well, in Pokemon Black, the story focuses on your journey as a new trainer in the Unova region, facing Team Plasma which has a radical view on Pokemon liberation. In Pokemon Black 2, it's set two years after the events of Black. The region has changed, and Team Plasma has split into two factions. One is still causing trouble while the other is trying to make amends. Also, there are new areas to explore and new Pokemon to encounter in Black 2.
Well, Pokemon Black's story starts with you as a young trainer in Unova. You meet various Pokemon and trainers. Team Plasma is causing trouble as they believe Pokemon should be free from human control. Black 2 then takes that story further. It shows how the Unova region has developed. There are new Pokemon evolutions. You have to face off against stronger opponents. The story is about growth, friendship, and the balance between humans and Pokemon in the Unova region.
The protagonist is still likely to be a young trainer starting their journey in the Unova region. There would probably also be a rival character, who might have different motives compared to the original. And of course, the Gym Leaders are important main characters as well.
The player character from Pokemon Black is also quite popular. Fanfiction writers can put their own spin on the character's journey, like adding more personal struggles or different goals than just becoming the Pokemon League champion. They can also give the character unique relationships with other characters in the game world.
Often, the main characters are trainers. They could be new trainers starting their journey in the Pokemon world of Black and White. Maybe a young and ambitious trainer who is eager to collect all the badges and become a Pokemon master.