Serena is a Pokemon trainer, and Ash's 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.
Serena is voiced by Mayuki Makiguchi (Japanese) and Haven Paschall (English).