If you're a huge fan of One Piece, then chances are you might be wondering how Oden's vassals became samurai. From the manga, we get to learn a lot about Oden and his past, and it is both good and bad from what we can tell.
He was exiled from the Capitol city, but happily, he found a home to rest his head via the city of Kuri. He even got the chance to meet new friends along the way, so it's safe to say things didn’t turn out all that bad after all.
Now, those around him are called vassals, and the latest chapter of the manga focuses much on how they became samurai in the first place, and why they are so loyal.
From what we have gathered, Oden's friends decided to pull off a dangerous heist in order to gain more gold, but it all failed after they were captured by someone who works for the Shimotsuki family. After being captured, a family member of Shimotsuki gave them money, and urged them to go forth and become Oden's samurai.
The backstory of his friends could have been better, but despite that, it is what it is and were fine with that.