What is the name of the underwater goddess in Ponyo?

The underwater goddess in Ponyo is Granmammare. She is Ponyo’s mother and a powerful sea deity associated with mercy and the ocean’s balance.

After Ponyo uses magic to become human, the ocean’s natural order is disrupted, causing a catastrophic tsunami and strange changes in the moon and tides. Granmammare meets Fujimoto, Ponyo’s formerly human father, and reassures him that the crisis can be resolved.

She sets a test for Ponyo and Sōsuke: Sōsuke must genuinely accept Ponyo whether she is a fish or a human. When he does, Granmammare allows Ponyo to become permanently human, provided Ponyo gives up her magical powers. This restores the balance of nature.

A common mix-up is confusing Granmammare with Fujimoto, who is Ponyo’s father and the film’s magic-using alchemist, or with Ponyo herself. Granmammare is also recognized by Sōsuke’s father as a goddess of mercy. The film was written and directed by Hayao Miyazaki and released by Studio Ghibli in 2008.