There could be a new character, a rival to Ash's dad from his younger days when he was an active Pokemon trainer. This rival could reappear in the fanfiction, causing some trouble or adding some drama to the story.
Perhaps in this fanfiction, Ash's dad was once a great Pokemon trainer but had to give it up for some reason. Now, as a fan, he lives vicariously through Ash. He could be the one who inspired Ash to start his journey in the first place. He might have told Ash all those amazing stories about Pokemon when Ash was a little kid, which planted the seed for Ash's love for Pokemon.
Well, family drama is a big theme. There could be conflict between Ash and Giovanni at first, as Ash may not be able to accept a villain as his father. Also, the theme of power struggle can be present. Since Giovanni has a lot of power in the Pokémon world, Ash might have to deal with the expectations or threats that come with being his son. And secrecy is also a theme, as Giovanni may have kept this fact a secret for a long time.
Sure. In some fanfictions, the revelation of Giovanni as Ash's dad can lead to interesting plot twists. It might make Ash question his own identity and purpose. Also, it could potentially change the relationships between Ash and his Pokémon friends, as they may have to deal with the implications of Ash having such a powerful and often - villainous father.
Since we don't have more details about 'Becky's dad adult stories', we can only guess about Becky's dad. He might be a father figure who experiences different events and has relationships with other characters in the stories. Maybe he is a kind father, or he could be facing some challenges that are central to the plot of the stories.
The dad of Peacemaker in the comics is Auggie Smith. Auggie's presence and actions have played a crucial role in shaping Peacemaker's journey and personality.