Serena is a Pokémon trainer of the Kalos region and one of Ash's traveling companions. Her goal is still unknown for the time being. She and Ash met before the start of the series, with Ash having helped her out. Having a crush on him, Serena always blushes when she looks at him or talks to him. And she met May as childhood best friends for a long time before Hoenn region. She also met Rusty (who is from the Dorkly webseries) as childhood. Rusty mistreats and comments her in a sexist way when they were at summer camp, then he develops a crush on her for her looks and completely forgot that they went to camp together. She remembers him back then and does not like him, making her feelings for Rusty the opposite of her feelings for Ash.
Despite the fact that Serena is Ash's newest female companion and has just started her journey, she met him when they were younger back in Pallet Town years ago at Professor Oak's Pokémon summer camp. Serena was lost in the woods while trying to look for the rest of her group but got herself wounded after getting startled by a Poliwag. At that same moment, Ash came to her rescue and escorted her out. Since that day, they have been together as childhood friends for a long time before Ash started his journey.
Serena is somewhat skilled at Rhyhorn Racing. She showed Ash how to ride a Rhyhorn, which shows she knows a lot from her mother teaching her about them. In the episode it is revealed that Serena does not like Rhyhorn Races, but throughout the episode she grew to like them better than before. On the day before the Rhyhorn Races, she baked cookies for Ash, Clemont, and Bonnie in the middle of the night. The next day, the Rhyhorn Races began, but it was interrupted as Team Rocket disabled the cameras. Serena became worried that something terrible might have happened to Ash, so she along with Clemont and Bonnie went off to see what was going on. When they found him, they discovered that he had been ambushed by Team Rocket and they find him trapped in a net while his Pikachu and the Rhyhorn were trapped in cages. As Clemont used his Bunnelby to trap Team Rocket in a ditch, Serena and Bonnie arrived to rescue Ash. Serena used her Fennekin to fight off Team Rocket and make them drop the remote. This indicated that this is her first Pokemon battle in her journey as a trainer. When Team Rocket was blasted off by the Rhyhorn they captured, she introduced her friends to her mother. She then tells her that she decided to travel with Ash and his friends. She thought her mother would disagree with her decision, but instead she said it would be a better experience for her. Afterwards, she gave her friends each a bag of cookies as a way of saying thank you to Ash for all he did for her.
Serena marks a return to basing Ash's female companion off of that generation's female player character. However, Serena is also the first to have undergone minor cosmetic changes for the transition to the anime, whereas May and Dawn remained the same. Among the cosmetic changes are:
She appears younger or shorter than her game counterpart.
The hair is a much darker shade, and seems slightly shorter.
Her skin tone is very faintly darker than her game counterpart.
Her fingernails are short and trimed like most other characters on the show, rather than long like her game counterpart's.
Her fingernails are kept natural without any nail polish on, while her game counterpart wears a faint pink nail polish.
Her shirt collar is white instead of black.
The sunglasses on the hat and the bracelet on her left wrist are absent (the bracelet depicted in her game artwork, though, is actually the Mega Ring).
Her eyes are blue despite the fact that her hair is not blonde like her game counterpart, where they should be grey, matching her current hair color.
The bow that's on her hat is not on her game counterpart.
Her hat appears larger, more curved, looking similar to a straw hat.
She wears shoes unlike her game counterpart, who wears sneakers; however they are in the same design.
The line going down from the top of her shoes, down to the soles, is one straight line, while on her game counterpart's sneakers, they are two seperate lines.
She also does not have the purse that her game counterpart does, instead having a backpack.
Serena's Braixen is a fire-type Pokémon owned by Serena. She made her debut when Serena got her through Professor Sycamore. She evolved from Fennekin during a performance battle with Aria when Serena assured her Pokémon things would be all right.
Pancham first appeared when he interrupted a Pokémon Showcase performance by dancing on the stage. But when Pancham stole Ash's hat and Clemont's glasses, the group went after him. However, when Serena found him first, she learned that Pancham had a desire to perform and decided to catch him.
Serena's Eevee first appeared gracefully dancing on a stage-like rock. Serena, charmed by Eevee's dancing, decides to befriend and catch Eevee. Serena soon gains Eevee's trust after saving her from Team Rocket, and then becomes Serena's third Pokémon. Though Eevee has a passion and love for dancing, she is a very timid Pokémon and would tend to hide behind Serena or Clemont's Bunnelby. Eevee later evolved into Sylveon during a double battle against James and Miette at a dance party. Since evolving, Sylveon is no longer timid and now has full confidence in herself.
Jigglypuff are usually famous for their sweet voice, but this particular Jigglypuff has a problem with its voice, so Ash and Co. helped it to regain its voice but Misty didn't catch it so whenever. There is also a chance that it will appear again in the XY series and Serena capture to Jigglypuff Its known moves are Sing, Double Slap and Pound.