Sonia

Sonia and Leon in their childhood

Sonia in the anime

Prior to Pokémon Journeys: The Series, Sonia was a childhood friend of Leon, and the two began traveling together when they became Trainers. However, a rift was formed in their friendship when Rose took an interest in Leon's potential and began mentoring him.

Sonia debuted in Toughing It Out!, where she overheard Ash and Goh's proclamations of Leon being a hero and mumbled to herself about it, which was noticed by the two young Trainers. Sonia explained to them about the golden statue behind them, which was modeled after the hero who stopped the Darkest Day.

As Ash introduced himself and his Pikachu, Sonia became infatuated with the Mouse Pokémon, gushing over Pikachu and caressing his ears, despite Pikachu's annoyance. She subsequently caressed Raboot's ears, being just as enamored with the Rabbit Pokémon. She then properly introduced herself as Professor Magnolia's assistant and granddaughter. Then, Sonia explained that it was her "homework" to study the Darkest Day.

In Sword and Shield, Slumbering Weald!, Sonia was driving a car to chase Dynamax energy falling from the sky, and she picked Goh up along the way. The two decide to travel together to find out what was happening in the region, without realizing that they were being followed by someone at Oleana's behest.

Sonia as a Professor

In Sword and Shield: The Darkest Day!, Sonia takes Goh to Turtfield, both visited the town to see its famous geoglyph, theorizing what connection it could have to Dynamax. From there, they head to Wedgehurst where Sonia introduced her grandmother to Goh and handed him a Dynamax Band from a Wishing Star that Sonia and Goh found. When they meet Magnolia, she tells about her progress in researching the Galar legend up until that moment, some time later they decide to travel to Stow-on-Side, but before that Magnolia warns her granddaughter and Goh about the danger that Rose represents. When she and Goh arrive at the city mural, they are approached by the mysterious man sent by Oleana, who decides to battle Goh. During the battle, Goh's Rabbot accidentally destroys the mural, thus revealing a statue of Zacian and Zamazenta.

Sonia as a teenager with Leon

In Sword and Shield: "From Here to Eternatus!", still studying the statue, Sonia and Goh are approached by more of Oleana's subordinates, which forces the two to flee. Their next stop after that is on Slumbering Weald, when they go deeper into the forest, Sonia and Goh meet the legendary Pokémon. Sonia and Goh end up finally finding the altar where Zacian and Zamazenta rested. Goh ends up finding the Rusted Sword and Rusted Shield and decide to leave for Hammerlocke where Ash and Leon were. Before they can enter the Hammerlocke Stadium, they have several Macro Cosmos thugs waiting for them, in order to buy time for Goh, Sonia asks him to move on. When henchmen use their Pokémon, Sonia with no way out is saved by Raihan's arrival.

In Sword and Shield... The Legends Awaken!, it is shown that Raihan managed to defeat the henchmen easily, with that and with the fury of Eternatus starting to destroy the place, Sonia decides to go to the place of the battle. There she finds Leon almost defeated and tries to help him. When everything seemed lost, Zacian and Zamazenta join Goh and Ash to defeat the Pokémon. When they finally defeat the huge Pokémon in its last form, Goh and Ash capture it, and Sonia and Leon thank them for their work. In the end, Sonia is seen talking about everything that happened. Magnolia decides to leave the responsibility of looking after Eternatus, now sealed in a safe, with her new position as Professor.

Like her game counterpart, Sonia is quite intelligent, though a little distracted. During her trip with Goh, she proved to be a wild driver, although she doesn't admit it. In the past she was Leon's childhood friend and traveling companion, much like the games, but their relationship changed as Leon became closer to Chairman Rose. This made Sonia decide to pursue her own course, far from what Leon was looking for.

During the time she was traveling with Goh, Sonia showed a good relationship with the young Trainer, including encouraging him to continue his research and indicating that he could be a Professor in the future.

Sonia in Pokémon: Twilight Wings

In Early-Evening Waves, Sonia comforted Nessa after the latter's defeat in the Champion Cup. She later talked to Nessa on the phone and learned about her future plans as a Gym Leader.

In Moonlight, she talked with Leon over the phone.

In Sky, she watched the battle between Leon and Raihan with her Yamper.

In The Gathering of Stars, she set off for the Crown Tundra. Before leaving, she handed Hop an invitation letter for the Galarian Star Tournament.

Sonia briefly appeared in GOTCHA!.

Sonia debuted in PASS06. She encountered her grandmother Professor Magnolia and her assistants Henry, Casey, and Marvin at the Budew Drop Inn. Sonia explained the inn's statue and its connection to the Darkest Day. When Magnolia's trailer broke down, she asked Sonia to go investigate the geoglyph at Turffield in her place. She later concluded the geoglyph was a drawing of the Darkest Day.

In PASS09, Sonia and Henry had dinner with Rose at the Captain's Table restaurant. Noting that Sonia was investigating the Dynamax phenomenon, Rose invited her to investigate the vault in Hammerlocke. Afterward, Sonia received a call from Nessa, who vented about her losses against Henry and Casey.

In PASS13, while in Hammerlocke, Sonia angered a wild Oranguru when she accidentally stepped on its fan. After being saved by Henry and Raihan, Sonia and Henry entered the Hammerlocke vault. Inside were four tapestries, each depicting events from the Darkest Day. Sonia and Henry noticed the tapestries portrayed two heroes instead of the singular hero like on the statue in the Budew Drop Inn. Sonia chose to stay and do more investigating while Henry went ahead with the others.

In PASS17, when an earthquake struck Hammerlocke, Sonia went to see if the Energy Plant was unharmed. She found Leon attempting to enter the building and check on Rose's safety, only to be blocked by a pair of Macro Cosmos employees. When Leon spotted her, Sonia attempted to flee, but was stopped when Raihan arrived. Raihan told Sonia and Leon to move the citizens to a safer location while he went inside to see if Rose was unharmed.

In PASS19, Sonia arrived in Circhester, where a fifth tapestry was said to be held at the Bob's Your Uncle restaurant. She later took Henry's group to the restaurant and told them what she had found out. She speculated the tapestry was thrown away on purpose to keep a piece of Galar's history out of public knowledge.

Later, Sonia planned to meet up with Henry's group and give them information she uncovered on Sordward and Shielbert, the thieves that stole Casey's Pokémon. Just as her Flying Taxi approached the meet-up spot, it was shot out of the sky by a Klinklang. After Leon rescued Sonia, he and Raihan took her and the Cabbie to a hospital in Hammerlocke. The camera containing the information meant for Casey was given to Piers for safekeeping until it reached its destination. Sonia later awakened at the hospital, where she revealed to Leon that Sordward and Shielbert were working together with Rose.

Sonia in Pokémon Journeys: The Series

Sonia appeared in JNM13 and JNM14, where she played the same role as she does in the anime.