Fanfan (ファンファン,Fanfan) is a girl that Master Roshi and Master Shen were interested in back in their days training under Master Mutaito. She would later become the ex-wife of Master Roshi, the mother of both Colonel Violet and Ranfan, and the mother-in-law of Hasky, though none of them are known to have discussed her much, which makes her an enigmatic character. Roshi left her at an unspecified time in the past, shortly before his twenty-year disappearance, and has implied that their marriage was not stable.
Fanfan has yet to appear in the series, and her exact status and, or whereabouts is currently unknown.
Goku met her when he used the Time Room to travel back in time to train under Master Mutaito. He first saw her when the young Roshi was spying on her taking a bath in a hot spring. During Goku's training, he retrieved a scarf that Fanfan had lost, and returned it to her. Roshi had been nearby, and quickly attempted to exploit Goku's gesture in an attempt to befriend Fanfan, claiming that he had given Goku "a few pointers."
Shen (who had been observing) became jealous and intercepted Fanfan a short while later as she was carrying laundry. Her attempts to ward off his advances infuriated Shen, and he punched Fanfan, knocking her out cold. Roshi had been following Fanfan and tried to rescue her on-the-spot, but Shen kicked him aside and told him to bring his "pet" (Goku) and meet him at Dead Field. Roshi hurried to find Goku, and the two rushed to Dead Field, where they found Shen waiting for them. Shen attacked Goku, but it quickly became clear that Goku was the stronger of the two. Shen then revealed Fanfan, still unconscious and tied to a tree, with one of his fellow students holding a knife over her, and threatened to have Fanfan killed if Goku so much as moved. Despite repeated attacks against his motionless opponent, Shen was still unable to defeat Goku, and finally threw a burning torch down to the ground, igniting the field and trapping Goku and Roshi in a circle of flames.
Using a technique he had learned from Mutaito, Goku managed to open a path in the flames so that he and Roshi could escape. Fanfan had meanwhile regained consciousness and incapacitated one of her captors with a kick. Another of Shen's friends was about to hit Fanfan, but was stopped by Mutaito, who had just arrived on the scene. With the crisis averted, Roshi again tried to cash in on Goku's skill, claiming that he had taught Goku the technique that allowed them to escape the flames and lamenting that Fanfan had not witnessed it. Fanfan smiled and revealed that she had not been unconscious the entire time, and had seen the true chain of events, much to Roshi's embarrassment. In the Japanese dub, Fanfan says she will support Roshi in becoming a great martial artist. Her fate after this is unknown, as whether or not she survived King Piccolo's rampage was never stated.