Christian is one of the leaders of the NG Fighters and one of the main characters in Dragon Ball NG. He is the brother of Goku and the son of Bardock and Fasha. he is a very skillfull fighter in the new Saiyan bunch.
Christian looks just like Goku with the exception that he has his Saiyan Armor on until the Cyborg Saga, in which Goku gives Christian his uniform. and so he keeps the outfit throughout the rest of the series.