Vegeta, the Saiya-jin prince. After Freiza killed his father, King Vegeta, he took the young guy in, and trained him to be his... slave, so to speak. He told Goku this in the Freiza saga, and made Goku understand that Freiza couldn't live, or he'd just do it again. After Freiza's death at the hands of Mirai Trunks, he was basically a "good guy". In Dragonball GT, he forgot about his original goal of killing Kakarott. The biggest mistake he ever made was marrying the multi-colored wonder, Bulma. Though he may not want to kill Goku anymore, he competes through the form of their sons, Trunks and Goten. That's about all for the Saiya-jin Prince's biography. Thank you.