In the “Wano” arc of One Piece, the sad death of Kozuki Oden was shown. This made fans wonder why Whitebeard, who cared so much about his crewmates, didn’t get revenge. Even though Oden joined Roger’s crew even though he was the Second Division Commander for the Whitebeard Pirates, Whitebeard and Oden were still close. Since they were both sworn brothers, one can only imagine how sad it was for Whitebeard and his crew when Oden died.
Whitebeard could have gone up against Kaido, but he didn’t. He had a large crew, a lot of treasure, and very skilled fighters on his side. Even stranger is that he went to war with the Marines to save Ace but did nothing to stop Oden’s death. Whitebeard didn’t do anything, but that doesn’t mean he wasn’t crushed by the loss. Here’s why Whitebeard didn’t kill Oden’s killers.
How Oden and Whitebeard got to know each other in One Piece

Whitebeard let Oden join his crew because he kept after him so hard. Soon after joining the Whitebeard Pirates and being thought of as Whitebeard’s younger brother, Oden worked his way up the ranks and became a commander. But then he left with Roger, but he and Oden were still on good terms.
Whitebeard stayed a pirate after Roger became King of the Pirates, but Oden never returned to him. But Oden did ask Roger to let Izou look after Whitebeard instead of him. You worked for the daimyo of Wano Country, Kozuki Oden, who later became the leader of the 16th division of the Whitebeard Pirates.
Why didn’t Whitebeard attack the Beast Pirates to get back at them for killing Oden?

Wano was cut off from the rest of the One Piece world, so the Whitebeard Pirates discovered that Oden died a few years later. At that time, Marco and the others did want to get even with Oden, but they didn’t do anything about it. As Emperor, Whitebeard had to take care of a lot of things. The safety of his whole crew and the people who lived in his territories and in his hometown depended on him. Whitebeard gave his staff two rules. One said they couldn’t kill anyone, and the other said they couldn’t take anyone’s treasure.
Whitebeard lived by these rules and told his crew to do the same. Whitebeard did the right thing by not letting his feelings get in the way of his decision. He knew that going into Wano would be dangerous and that having two Yonko fight each other would be a disaster.
No one would have anything to gain from that war. Both sides, as well as the people of Wano, would lose a lot of people. So, Whitebeard decided that getting revenge wasn’t worth putting the lives of his men and the Wano people, who Oden had fought so hard to protect, in danger.