Obviously, Ash and Jolteon are the main characters. Ash is the trainer, and Jolteon is his Pokémon. But there could also be other characters from the Pokémon universe that might be involved, like Ash's friends or other trainers he meets along the way.
Ash and Jolteon are the main ones for sure. Ash is the central human figure, and Jolteon is the Pokémon that the fanfiction seems to focus on. However, in many Pokémon - related fanfictions, there are often side characters that enhance the story. So, it's possible that some of Ash's rivals or even new characters created by the author could also be important in this fanfiction. For instance, a new villain who wants to steal Jolteon for its power. These additional characters can add more depth and conflict to the story centered around Ash and Jolteon.
Chapter 31 is the strongest chapter-level answer because it starts from Before Shen Lan had reached the backyard, she already heard the sounds of... and follows through on After staying in the study and reading for another day, she finally....
Look to Chapter 34 for the clearest answer. It begins with Seeing that the public sentiment wasn't quite right, Su Yinwan felt..., keeps building through It was she who had anonymously paid someone to write the critical article..., and lands on Now that Lili is misunderstood, they start to kick us.
Chapter 730, "How Can You Make a Deal with a Madman?!", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Xu Ning's emotions grew more intense as she spoke.
Chapter 909, "Hexin Sanatorium", is the clearest early answer because it turns Jiang Buchen's situation into a concrete plot event.
Chapter 794, "Debut as a Group!", is the clearest early answer because it turns God Jiang's situation into a concrete plot event. Early on, Everyone crowded around Shi Xu as he entered the living room.. By the end, After narrowly missing out in season one, he came back in season two....
A practical answer is Chapter 31, because it turns the idea into a concrete scene. The chapter opens with Before Shen Lan had reached the backyard, she already heard the sounds of..., adds pressure through And judging from the photo, she was also a stunning natural beauty!, and ends on After.
Chapter 899, "It's actually a seal script?!", is the clearest early answer because it turns Rong Kexi's situation into a concrete plot event. The chapter gives readers a real answer by opening on Jiang Cheng, with his head dizzy, was pulled into the courtyard by...
Look to Chapter 34 for the clearest answer. It begins with Seeing that the public sentiment wasn't quite right, Su Yinwan felt..., keeps building through It was she who had anonymously paid someone to write the critical article..., and lands on Now that Lili is misunderstood, they start to kick us.
If you want the clearest chapter reference, go to Chapter 11. Early on, After a meeting, Shang Shaojing pinched the bridge of his nose, tired, and...; later, the chapter leans on How is it going with the Jiang Family?" The assistant looked troubled and....