Eiichiro Oda is an extremely talented mangaka, and many consider him to be the greatest of all time. Oda's One Piece is mainly known for its excellent world-building, which causes the other aspects of the story to go under the radar. The characters created by Oda have immense backstories, which makes them more relatable.
However, not every character gets the same quality backstory. In fact, some of them are quite underwhelming, and they are not able to evoke emotions. With that in mind, here are some One Piece characters that needed better backstories.
6 Roronoa Zoro
Roronoa Zoro is one of the most powerful characters in the series. From the very beginning, he has expressed his desire to become the strongest swordsman in the world. Zoro's ambition is directly linked to his childhood. When he was still living in the Shimotsuki village, Zoro became rivals with Kuina.
The two had many duels, and Kuina came out on top every single time. She was extremely talented, but unfortunately, her life ended in tragic fashion. Kuina was declared dead after she fell down the stairs. It was quite a bizarre way to kill off a character, and it didn't have the same level of impact. Considering Zoro was motivated by her death to become the greatest swordsman, it could have been handled in a better way.
5 Usopp
Usopp is the sniper of the Straw Hat Pirates. He joined the crew in Syrup Village, and he has helped them to get out of many dangerous situations. He played extremely important roles in the Enies Lobby arc and the Dressrosa arc. Usopp's backstory is also sad, but it seems pretty generic by One Piece standards.​​​​​
Usopp's father, Yasopp, left his family in order to sail with the Red Hair Pirates. Usopp never held the decision against his father, but there's no doubt that Yasopp's departure had consequences. When Usopp's mother fell ill, he could only try to comfort her with his lies. ​​​Usopp grew up to become a compulsive liar, and he did his best to trick the people around him. The backstory is rather simple, and it is mainly used to create empathy. Again, it is not necessarily a bad backstory, but in comparison to the rest of the Straw Hat Pirates, it is nothing special.
4 Senor Pink
The common consensus is that Senor Pink's backstory is extremely heartbreaking, but on closer inspection, it just seems like a way to rescue his character. Senor Pink was a horrible human being who lied to a woman in order to marry her. He kept on feeding her lies until their child died.
Senor Pink then started to dress up like a baby after he managed to get a reaction from her. While he did change his clothes, Senor Pink was still working for Doflamingo, and he never atoned for his sins.
3 Kaido
Kaido was the main antagonist of the Wano Country arc. He was hyped as an incredibly dangerous character since the Punk Hazard arc. When the time came for Kaido to make his debut, he made sure to have the most jaw-dropping introduction. He casually fell from a sky island and crashed into the ground. Kaido had no visible injuries except for a minor headache.
This moment solidified Kaido's reputation, and it made sure that the next time he appeared in the story, fans would get off their seats. In the Wano Country arc, as Luffy edged closer to victory against the Emperor, Oda finally revealed his backstory. The flashback was good, but it was extremely terse, and it left a lot to be desired. It didn't expand on whether Kaido fought his captain or why he ran away from the crew.
2 Yamato
Yamato is one of the several new characters introduced in the Wano Country arc. He calls himself Oden because he was inspired by the samurai's persona. When Kaido discovered his son's desire to be like Oden, he immediately imprisoned him.
Yamato spent most of his life in shackles as a prisoner of Kaido. This particular backstory was too similar to that of Sanji, and it didn't really help Yamato stand out as a character. The backstory did not have many impactful moments. It didn't really help the audience understand why exactly Yamato wanted to be like Oden, except for the fact that he read his journal.
1 Caesar
Caesar made his debut in the Punk Hazard arc, and he was the main villain. Before being associated with pirates, Caesar used to work with Dr. Vegapunk. The two worked on many different projects, but eventually, Caesar strayed from his path. He began working on a massive project that involved the creation of poisonous gas. This weapon could wipe out entire towns with ease, making it illegal.
As a result, Vegapunk kicked Caesar off the team, which fueled their rivalry even further. Caesar decided to use the weapon, which resulted in the destruction of two laboratories. He was captured, but he managed to escape from the prison ship. After a year's absence, Caesar returned to Punk Hazard and began operating in secret. As one of the major villains, Caesar's backstory is too simple. It shows that Caesar lacked any real motive except to prove that he was a better scientist than Vegapunk.