Serena is a Pokémon trainer and Ash's long-lost childhood friend. She remembers Ash from their childhood when the two of them attended the Oak summer camp in Pallet Town. During this time, Serena had fallen and injured her leg; Ash then helped her with her injury, causing Serena to fall in love with him. After seeing Ash on TV, and still having feelings for him, she decided to leave home to reacquaint herself with Ash, and upon doing so, comes along with him on his journey despite having no specified goal. But after experiencing numerous events like the Sycamore summer camp, she learns about Pokémon Showcases from Shauna, and decides to become a Pokémon Performer.
- She is voiced by Haven Pascall.
- Serena is mainly one of Ash's girlfriends in Ash's Adventures, alongside Misty, May, Dawn and Lillie.
- Serena will be mentioned by Ash during a conversation with Max Goof in Ash's Adventures of A Goofy Movie and will fully introduce her to him and his father in Ash's Adventures of An Extremely Goofy Movie.
- Serena will make a surprise guest appearance at the end of Pooh's Adventures of Rugrats in Paris: The Movie.
- Serena will meet Team Robot in Team Robot In Pokemon XY The Series.
- In Noby Ran Away from Home: The Musical, she and May became rivals over Ash and who will be his girlfriend.
- Serena also confesses her love for him possibly in Pokemon XYZ The Series.
- In the series, Power Rangers Data Squad, Serena will have a love interest for Robbie in his brave courage and a strong heart.