Since Ash has Mega Charizard in the Sinnoh fanfic, it could change the whole power dynamic. Charizard is already a very strong Pokémon, and in its Mega form, it's even more so. This could lead to new rivalries. For example, other trainers with strong Pokémon might see Ash as a bigger threat now and challenge him more often. Also, it could play a role in Ash's journey to understand different Pokémon types better, as he might rely on Mega Charizard's strength in certain situations and then learn about the weaknesses of other types in the process.
In the Sinnoh fanfic, having Mega Charizard gives Ash a significant edge. It could potentially change the story's direction completely. For instance, he might be able to take on Pokémon Contests in a different way if he uses Mega Charizard's power. He could use it to create unique battle strategies that no one in Sinnoh has seen before. This could also lead to some interesting interactions with Sinnoh's native Pokémon. Mega Charizard's presence might intimidate some Pokémon, while others might be curious and want to battle it. And it could also affect Ash's relationships with his friends in the fanfic. They might look at him in a new light, either with more respect or with a bit of envy.
Well, it could mean that Ash has an extremely powerful ally in the Sinnoh region. Maybe he uses Mega Charizard to battle against powerful gym leaders or face off against the evil teams more effectively. It might also attract the attention of other trainers who are either in awe or jealous of his powerful Pokémon.
It's possible that he received it as a gift from Professor Oak. Oak might have discovered a way to transfer Mega Stones across regions and sent the Charizardite to Ash in Sinnoh. Another option could be that Ash made a trade with another trainer. He traded one of his Pokémon for the Mega Stone, knowing the potential of Mega Charizard.
The plot could be that Mega Charizard Y gets injured in a battle. Ash then has to search for a rare healing item in a dangerous, uncharted part of the Pokémon world. He faces many obstacles and other trainers who are also after the item. All the while, Mega Charizard Y is recovering slowly, and Ash is determined to get the item in time to fully heal his beloved Pokémon.
One possible plotline could be that Ash and his Mega Charizard embark on a journey to a new, uncharted region. There, they face a powerful new villain with a team of never - before - seen Pokémon. Along the way, Ash has to train Charizard even further to unlock new Mega Evolutions. They meet new friends who help them in their battles and exploration.
Well, it might mean that Ash is bringing his powerful and experienced Charizard into the Kalos region for some epic battles. Maybe he wants to show off Charizard's strength against the unique Pokemon in Kalos.
One possible plot could be that Ash realizes Charizard has grown too powerful for the current region he's in and decides to release it so it can find a more challenging environment. Maybe it goes off to a far - off mountain range where it battles and befriends other powerful Pokémon.
Well, perhaps there could be a great battle where Charizard's mega evolution is the key to victory. Ash enters a tough Pokémon tournament, and in the final match, his opponent has a really strong Pokémon. Charizard mega evolves and unleashes a super - powerful attack that wins the battle for Ash.
One possible fanfiction could be that Ash discovers a new power within Mega Charizard Y during a crucial battle. This power could be a unique type of fire blast that has the ability to heal his Pokémon as well as damage the opponents. The story could revolve around Ash training Mega Charizard Y to master this new power and use it to defeat a powerful villain in the Pokémon world.
Another theme is growth. Ash may grow as a trainer, learning new strategies to better utilize Mega Charizard's powers. And Charizard might also grow in strength and in its understanding of Ash's commands. For example, they might face a powerful enemy that forces them to adapt and become stronger together.
The plot could be that Ash is in Kalos to participate in a special Pokémon tournament. Misty hears about it and decides to come support him. Charizard, of course, is Ash's main battling Pokémon. Along the way, they meet a new type of Pokémon that is causing trouble in the region. They have to figure out a way to stop it, with Charizard using its powerful attacks. And in the end, Ash wins the tournament with the help of Misty and Charizard.
It could be about Ash and his Charizard training to master the blue flames. Maybe they encounter a powerful enemy that can only be defeated with this new, more powerful form of Charizard's flames.