Power and growth are also typical themes. Having Reshiram gives Ash new power, and he has to grow in order to handle it properly. The fanfics usually show how he learns to control Reshiram's power and how it affects his battles. For instance, he might face stronger opponents but with Reshiram, he has new strategies to overcome them. Also, the theme of trust is important. After the betrayal, Ash has to learn to trust again, this time with Reshiram, and the story often explores how this trust develops over time.
There's also a fanfic series that delves into this concept on Archive of Our Own. In it, Ash's betrayal is a turning point. Reshiram comes to him as a symbol of new hope. The story is really detailed in exploring Ash's emotions and his new relationship with Reshiram. For example, it shows how he trains with Reshiram and how they face various challenges together. It's a great read for fans of this kind of scenario.
One common theme is adventure. Ash and Reshiram might go on a journey together to discover new Pokémon or solve some mystery in the Pokémon world.
One common theme is revenge. After being betrayed, Ash often seeks revenge on those who wronged him, which leads him down the path of evil.
A third common theme could be self - discovery. Ash is constantly growing and learning in the Pokémon series. With an anthro Reshiram by his side, he might discover new aspects of himself, his powers, or his place in the Pokémon world. The fanfic could also explore how Reshiram, as an anthro character, has its own journey of self - discovery and how their paths intertwine.
A typical sign is his disregard for the well - being of others. Previously, Ash might have been a selfless character, but after betrayal, he may start to use people for his own gain. Also, his appearance might change in the fanfiction. He could start to dress in darker colors or have a more menacing look in his eyes, symbolizing his inner transformation.
A common theme could be the exploration of femininity within a powerful and mythical Pokémon like Reshiram. Another might be relationships, like with a trainer or other Pokémon.
One common theme could be the loss of innocence. Ash has always had a somewhat naive view of the Pokemon world, and Mew's betrayal would shatter that. It would make him realize that not all Pokemon, even those seen as pure and good like Mew, can be trusted blindly. Another theme might be the power struggle. Mew is extremely powerful, and its betrayal could be part of a larger power play in the Pokemon world. Ash, as a relatively small - but determined - trainer, would have to find a way to deal with this power imbalance.
Power struggle can also be a theme. If Diantha betrays Ash for power, it shows how power can corrupt and change a person's values. It could also lead to a battle of wills between them, as Ash might try to oppose Diantha's new -found power - hungry ways. This theme often explores the darker side of human (or in this case, trainer) nature when faced with the allure of power.
One common theme is friendship. The human and Reshiram often start as strangers but gradually become friends, relying on each other in various situations. Another theme is adventure. They usually embark on some sort of journey, whether it's to save a region or to discover something new about the Pokémon world.
A common theme is the power struggle. Given their different natures and powerful abilities, many fanfictions explore how kyurem and reshiram deal with the balance of power between them. Another theme is friendship or alliance. Despite their differences, they often come together in fanfictions, either out of necessity or a growing understanding of each other.