One way to create engaging characters is through their relationships. A character could be Brawly's long - lost relative who shows up unexpectedly. Their relationship can be full of tension, love, or a mix of both. Additionally, create characters with different fighting styles. A character who uses unconventional Pokemon and battle strategies can be very interesting. They can challenge Brawly's traditional ways and lead to some great story developments.
You can make characters engaging by giving them quirks. For instance, a character who always wears a strange hat and has a superstition about never taking it off during battles. Also, consider their goals. If a character's goal is not just to win battles but to understand the emotions of Pokemon better, it adds depth. This can be explored in relation to Brawly, who might have his own views on Pokemon and training. By having characters with different views interact, it becomes more engaging.