Character Description
 Plot involvement
Baba (Full title: Fortune Teller Baba) is one of the many lesser characters in the DragonBall universe. Sister to Master Roshi she is a shrewd business woman, and makes a living by charging extortionate fees for her services as a mystic, using her crystal ball and links with the afterlife. If they can't afford to pay for her services, she offers them the chance to pay by winning her Martial Arts Tournament, which they never do since the opponents are hand-picked freaks from the afterlife and the demon world.
Baba first meets Goku when he comes to her seeking information on the whereabouts of the DragonBalls. After defeating all her usual fighters in the tournament, he is pitted against a mystery fighter that is later revealed to be his late adopted grandfather and original sensei, Gohan. Immediately after the tournament Baba predicts that Goku will one day save the world, and she is also present to see it happen during Goku's epic battle with Piccolo Jr.
In DragonBall Z Baba's role is pushed further into the background, where she helps out mostly by letting Goku's friends watch his battle with Vegeta from the safety of Roshi's home, Kame House, via Baba's Crystal Ball.
During the Majin Buu period of DragonBall Z, Baba is involved in more important matters by arranging for Goku to be allowed one day in the living world to take part in the Martial Arts Tournament with his sons and Vegeta, and is later seen accompanying the then-deceased Vegeta to the battlefield to fight Majin Buu alongside Goku.
During DragonBall GT, Baba is not really involved or even seen, and the afterlife/mysticism-related acts are performed by Kibitoshin and the Elder Kai.