His relationship with Pikachu might become more competitive at first. Since Ash already has a strong starter in Charmander, Pikachu might feel the need to prove itself more. But over time, they could learn to work together better, with Pikachu using its electric attacks to complement Charmander's fire attacks in battles.
His relationship with Pikachu would become quite different. Pikachu might have to take on a more protective role. Instead of Ash being the one in charge, Pikachu would be looking out for Eevee - Ash. They would still have a strong bond, but it would be based more on Pikachu's guardianship now.
Ash's character development is quite significant. At first, he might be a bit over - eager and not fully understand Charmander's needs. But as they spend time together, he learns patience. He realizes that Charmander can't always be pushed to its limits right away. His confidence also builds. When they win battles together, he starts to believe in his own abilities more. And his sense of loyalty deepens as he would do anything to protect Charmander.
It would change his journey a great deal. Firstly, having a shiny Charmander would make him stand out more. Other trainers would be more likely to challenge him, either to prove themselves against someone with a rare Pokémon or to try and get his Charmander. Also, trainers with more experience might offer to help Ash train his shiny Charmander, which could lead to new training techniques. In Pokémon contests, his shiny Charmander would be a show - stopper, giving him an edge in those aspects of his journey as well.
Their relationship grows through battles. Every time they face a tough opponent together, their trust in each other deepens. For example, when they battle a Rock - type Pokémon that is strong against Charmander's fire attacks, Ash comes up with a creative strategy that involves using Charmander's speed. This makes Charmander realize that Ash will always find a way to make them victorious.
Ash would likely be more confident from the start. Since he has a powerful Charmander, he might be more eager to take on stronger opponents. He would also have to learn how to handle a Pokemon with such great power, which could make him more responsible.
It makes his relationship with other trainers rather unique. Other trainers might view Ash with a mix of awe and envy. Since he was raised by Legendary Pokemon, they may assume he has some special training methods or insights. Some trainers might be eager to learn from him, while others could be intimidated and see him as a rival to be defeated at all costs.
In this fanfiction scenario, Ash and Charmander could have an adventure in a volcanic area. Since Charmander is a fire - type, it would feel right at home there. They might discover a new type of Pokemon that is only found in volcanic regions. Also, Ash could participate in a local fire - type Pokemon tournament in this area. With Charmander's growth and training, they could potentially win the tournament and gain some rare items or Pokemon eggs as rewards.
You can try fanfiction websites like FanFiction.net or Archive of Our Own. Just search for 'Ash starts with Charmander' on their search bars and you might find some interesting stories.
His Pikachu might feel a bit jealous at first. But eventually, they would all accept Mew as part of the team. Ash would have to spend more time getting to know Mew's unique abilities, which might mean less training time for the others temporarily. However, in the long run, Mew could teach the other Pokemon some new tricks.
One popular type of Pokemon Ash and Pikachu fanfiction might be adventure - based. For example, Ash and Pikachu could embark on a journey to a new and mysterious region filled with undiscovered Pokemon species. They might face challenges like difficult terrains and powerful, previously - unseen Pokemon. In this fanfiction, Pikachu's electric powers could be enhanced in some unique way, and Ash would have to strategize differently to overcome the obstacles.