From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
Son Goku met her when he used the Pendulum Room to travel back in time to train under Mutaito. He first saw her when the young Turtle Hermit 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. Turtle Hermit had been nearby, and quickly attempted to exploit Goku's gesture in an attempt to befriend Fanfan by claiming that he had given Goku "a few pointers".
Crane Hermit, 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 Crane Hermit, and he punched Fanfan, knocking her out. Turtle Hermit had been following Fanfan and tried to rescue her on-the-spot, but Crane Hermit kicked him aside and told him to bring his "pet" (Goku) and meet him at Dead Field. Turtle Hermit hurried to find Goku, and the two rushed to Dead Field, where they found Crane Hermit waiting for them. Crane Hermit attacked Goku, but it quickly became clear that Goku was the stronger of the two. Crane Hermit 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, Crane Hermit was still unable to defeat Goku, and finally threw a burning torch down to the ground, igniting the field and trapping Goku and Turtle Hermit 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 Turtle Hermit could escape. Fanfan had meanwhile regained consciousness and incapacitated one of her captors with a kick. Another of Crane Hermit's friends was about to hit Fanfan, but was stopped by Mutaito, who had just arrived on the scene. With the crisis averted, Turtle Hermit 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 hadn't witnessed it. Fanfan smiled and revealed that she hadn't been unconscious the entire time, and had seen the true chain of events, much to Turtle Hermit's embarrassment. Her fate after this is unknown, as whether or not she survived Piccolo Daimao's rampage was never stated.
- Fanfan's facial appearance and hair are similar to that of Colonel Violet, therefore it is likely that Fanfan is a re-used character design for filler purposes.
- Fanfan's name is almost the same as that of Ranfan aside from being spelled with an 'F' instead of an 'R'.