In Studio Ghibli’s Ponyo, the five-year-old boy who befriends Ponyo is Sōsuke.
Sōsuke lives with his mother, Lisa, in a house on a cliff overlooking the sea. He discovers Ponyo after she becomes trapped in a glass jar while exploring the ocean. Their friendship drives the film’s central story and helps bridge the human and underwater worlds.
Sōsuke is kind, observant, and unusually responsible for his age. He visits the elderly residents at the nursing home where Lisa works and quickly accepts Ponyo despite her mysterious origins. His promise to care for her becomes especially important when Ponyo’s transformation causes a dangerous imbalance in nature.
The name is sometimes written “Sosuke” without the macron in English-language material. Sōsuke should not be confused with Sosuke from other Japanese animated works; this character belongs specifically to Ponyo, Hayao Miyazaki’s 2008 film.