Ash might become more conflicted. He has always been on the side of good, but with Giovanni as his father, he'd have to grapple with his family ties. He could become more secretive and brooding as he tries to figure out how to balance his own values with this newfound family connection.
Sure. In the Pokémon community, there are numerous fan-created ideas. The idea of Giovanni being Ash's father has some interesting implications. It could potentially change the whole dynamic of Ash's journey. Fanfiction writers often take such unique concepts and run with them, so it's very possible to find such a fanfiction if you search in the right places, like some dedicated Pokémon fanfiction websites.
Ash would likely become more responsible. Since Dratini is a relatively rare and potentially powerful Pokémon, he'd have to take extra care. This could make him think more before acting in battles and other situations.
Ash would likely become more confident with a Rayquaza as his starter. Having such a powerful Pokémon would give him an edge in battles, and he'd grow in his leadership skills as he commands Rayquaza. He might also become more responsible, knowing that he has to take care of such a rare and strong Pokémon.
One possible plot could be Ash gradually discovering the truth. He might start noticing strange similarities between himself and Giovanni. Then, Giovanni could be torn between his role as the leader of Team Rocket and his newfound feelings for his son. Ash, on the other hand, would have to grapple with the idea of his father being a villain.
Ash could also develop better leadership skills. As an assistant, he might have to lead small teams during research expeditions. He would need to make decisions quickly and fairly, considering the safety and goals of the team. This would be a big change from his usual role as a solo trainer, and it would shape him into a more well - rounded character in the fanfiction.
His relationship could change in terms of training. Ash might start to incorporate some of Giovanni's more strategic training methods (assuming he learns about them). However, his Pokémon might be resistant at first, as they are used to Ash's traditional and more friendly training style. But over time, they could adapt and become even stronger. Also, Ash's Pokémon might have to deal with new rivals associated with Giovanni, which would test their loyalty and determination to stay with Ash.
In this fanfiction, Ash's character would develop in several ways. First, he'd become more empathetic towards Pokémon that are seen as difficult or 'bad tempered' like Deino. He'd have to understand Deino's needs and fears to build a strong bond. Also, his leadership skills would improve as he'd need to lead Deino in battles and on their adventures. He might also become more resourceful, finding new ways to keep Deino happy and healthy, like searching for specific types of food that Deino likes.
Often, it's portrayed as a complex relationship. Since Giovanni is typically seen as a villain in the Pokémon series, the fanfiction might show a struggle between Ash's good - natured self and Giovanni's more self - interested motives. For example, Giovanni might try to manipulate Ash into joining Team Rocket.
Another idea is that the discovery of Giovanni as his father makes Ash question his own identity and place in the Pokémon world. He might have to reevaluate his goals and his relationships with other characters. Meanwhile, Giovanni could be faced with the challenge of trying to make amends or trying to bring Ash into his world in a more positive way.
Ash would likely become more open - minded. Meeting a shiny ghost pokemon at the start would expose him to a type of pokemon he might not have expected so early. This could make him less fearful of the unknown in general. For example, he would be more willing to explore spooky places or deal with pokemon that have a reputation for being difficult to handle.