Rongo (ロンゴ) is Ahem's daughter and the water spirit. Centuries ago, she was engaged to Ongo until he became evil and they were split up. Much later, in 2009, Rongo spotted Ongo in Tokyo with Mii. Believing that Mii had taken the form of a 10-year-old and taken Ongo for herself, Rongo took over the body of Natsumi's friend Nami, and tried to remove Natsumi's skull necklace only to receive an electric shock.