Marissa is a one-off character who appears in "The Crystal Onix" alongside her older brother Mateo.
Looking for answers about the legendary Crystal Onix, Marissa threw a bottled message into the ocean asking anyone with information to visit her on Sunburst Island. When Ash and his friends found the letter, they tracked her down. They arrived to find her being hassled by a rival shop owner who wanted Mateo to shut down his business. Ash couldn't help with the Crystal Onix itself, but he offered his support anyway.
Marissa comes across as genuinely sweet and deeply loyal to her brother. She's the kind of person who believes in Mateo even when he doesn't believe in himself—always ready to pitch in and help however she can.
Content compiled by AnimeList.moe from publicly available sources.
