Sonia is the assistant and granddaughter of Professor Magnolia and friend of Leon
. She met Ash Ketchum
in the stadium after the Master Class battle between Leon
. She explained to them that the big statue in the stadium was based on the legend of a young famous Galar region hero bearing a sword and shield that defeated gigantic Pokémon long ago. Her driving skills are quite erratic as she made Goh
sick while he traveled with her in her car.
She is studying to become a Pokémon Professor. Part of the reason she wanted to become a professor is she wants to stay close to her grandma but it's mainly because of Leon
. They both love Pokémon, so they both wanted to become strong Trainers. When she was younger, she was the one who taught Leon
about Pokémon battles but once he made his debut as a Trainer, his talent as a Trainer was far better than hers and there was no way she could've trained hard enough to be able to defeat him. She figured there was a different path she could take that still involved Pokémon and that was to work hard to become a Pokémon Professor.
After researching the legendary heroes and finding out that they were Zacian and Zamazenta, she then became a Professor and was giving her lab coat.