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.
First, know the characters well. Ash is known for his courage and determination, and Reshiram is a powerful and majestic Pokemon. Create an interesting plot, like maybe they meet in a mysterious place. Then, build their relationship gradually. For example, start with Reshiram being cautious around Ash and then growing to trust him.
One great 'ash and reshiram fanfiction' is 'Ash's Reshiram Adventure'. It has an exciting plot where Ash discovers a lost Reshiram and they form a strong bond to face various challenges together. Another good one could be 'Reshiram's Choice' which focuses on how Reshiram decides to help Ash in his journey to become a Pokemon master. There are also many others on fanfiction websites like FanFiction.net and Archive of Our Own.
An interesting take on the Pokémon world is also important. Maybe the fanfiction is set in an alternate universe where the rules of Pokémon battles are different, and Ash has to adapt with Reshiram by his side. This kind of creativity can make a fanfiction stand out.
In some fanfictions, Ash might become evil after betrayal when his trust is shattered. For example, if his friends turn on him for some false accusations, he could start to see the world in a different, more cynical way. This broken trust might lead him to believe that power is the only thing that matters, and he starts to pursue it without regard for the consequences, gradually turning evil.
Well, I've come across some. One interesting one had Ash and Reshiram forming a unique bond during a battle against a powerful dark - type Pokemon. The author did a great job of showing how their connection grew over time. Another one was more about Reshiram seeing Ash's pure heart and deciding to stay by his side to protect him in his journey.
You can start by looking on fanfiction websites like FanFiction.net or Archive of Our Own. They have a vast collection of fanfictions, and you can simply search for 'Ash Reshiram' in their search bars. Many writers post their works there, and you're likely to find some great stories.