33 years ago, Whitebeard left the Rocks Pirates after the death of his captain and begin his own crew.
Three years later, the Whitebeard Pirates were shipwrecked on the Kuri region of Wano Country after climbing the waterfall and lost their supplies.
Whitebeard senses someone rapidly approaching them so he tells his crew to step back. Before they could figure out their next course of action, Kozuki Oden rushed to the scene and faced against Whitebeard.
Oden clashes with Whitebeard creating what it seems a Conqueror’s Haki clash, as indicated by the black sparks.
In a Luffy-like moment, but in reverse, Oden asks Whitebeard to join his crew and become his Nakama. This marks the beginning of Oden’s adventures as Pirate!
It is currently unknown how long Oden was a member of the Whitebeard Pirates before joining the Roger Pirates as well as how well he got along with the other members of the crew.
However, it is implied that because of his status as a Division Commander of the Whitebeard Pirates, he had a great amount of respect within the crew, and had the respect and leadership over the lower members of the Yonko’s crew. According to both Inuarashi and Sengoku, Whitebeard was greatly fond of Oden.
Could Oden have taken the position of 2nd Commander of the Whitebeard Pirates? That spot was available for a long time, apparently. And it looks like when Oden joined, Izo went along with him. And maybe Inuarashi and Nekomamushi too? Probably acting as retainers to “protect” Oden.