Bulma
Bulma is Goku's friend. As a teenager of 16, she origanally persuades Goku to join her journey to find the 7 dragon balls.
A vociferous and pushy person, her reason to collect them is to fullfill her wish to find a boy freind. She ends up falling in love with Yamcha, who is a friend and fighter with Goku.
Her father Dr. Briefs is the proud owner of the machinery company Capsule Corp. Bulma is also machanically inclined. She invented a dragnon ball radar, which detects dragonballs, enabling her to track them down.
After the journey, she joins Goku on a trek to find the dragon ball with 4 stars on it, which is inherited from Gohan. However, she regrets joining, as Goku confronts the red ribbon army. Bulma also plays a role in the planet Namek episodes, for her and her father are responsible for building the space ship that takes Goku, Krillin, Gohan, and herself to the doomed planet. On Namek she is left alone most of the time and gets into a little trouble with Captain Ginyu.
After the warriors arive back to earth, she develops a relation ship with Vegeta. By that time the Andriods 19 and 20(Dr. Gero) appear, Bulma has Given birth to Trunks. Later on she creates a wristwatch for Gohan that allows him to transform into " Great Saiyanman". 10 years after the death of Buu, she has anoter child, a daugther named Bra.
In the alternate future she builds a time machine for Trunks to go back in time to warn Goku about Andriod 17 and 18.