Kozuki Oden was also the only person in the Whitebeard Pirates who addressed Whitebeard as "brother."
Unlike the rest of them, who were "sons," Oden was treated by Whitebeard as a brother.
Originally, Oden had promised Whitebeard to accompany Roger on his adventures for two years before returning to the Whitebeard Pirates to sail with everyone once again.
Chapter 129