By now, pretty much everyone knows that Oda is an expert craftsman with regards to weaving backstories. Whether happy, mild, or tragic, all kinds of backstories one can think of are within Oda's area of expertise and, by extension, One Piece. With that being said, even though Oda does possess the skill to create a masterpiece of background for most relevant characters, sometimes he chooses not to.
When a character’s tragic past is revealed, they are put in the spotlight. Fans will find it easier to comprehend their motives, understand them on a deeper level, and sympathize with the villains – emotions a creator might not want a fan to have for a bad guy. That said, there are indeed villains in One Piece with pasts that are relatively tragic; they are just a few and far between.
10 Tragic Backstory: Brulee
Brulee’s backstory is much lighter in comparison to most of the tragic backstories in One Piece. Nonetheless, that doesn’t make it any less tragic. Big Mom raises her children as assets rather than actual children. It’s like a wilderness where the strong feasts on the weak.
The weak kids would be deemed useless; peasants for the stronger kids to practice their authority on. Brulee was a victim of such intense bullying and the scar on her face was the aftermath.
9 Unknown: Rob Lucci
Rob Lucci and his gang of CP9 were a major hurdle on the journey of the Straw Hats. During their showdown against the agents, each of the Straw Hats experienced a meaningful upgrade or two. It can’t be stressed enough just how vital the Enies Lobby Arc was to the future development of the main characters.
Rob Lucci, alongside his colleagues, fought and fell as a CP9 agent. Fans learned almost nothing of value with regard to his past.
8 Tragic Backstory: Arlong
Even though Arlong’s past was revealed after the timeskip, it wasn’t enough to excuse whatever dirty actions he committed. Yes, it did garner him sympathy, but that was the extent of it.
Arlong sailed alongside Fisher Tiger prior to the latter’s departure. Abroad Fisher's ship, he was exposed to many dirty and racist remarks from humans. The last straw that pushed Arlong to the dark side was Fisher Tiger’s tragic demise.
7 Unknown: Crocodile
Out of all the major villains, Crocodile’s unknown past seems to be the most intriguing. It still remains the subject of many fan theories, both viable and hilariously far-fetched ones. To put it into perspective, his past was so extreme that Ivankov used it to tie his hands back during Impel Down.
Hopefully, fans get the full details of his backstory before the series’ end, otherwise, it would be a big bummer.
6 Tragic Backstory: Big Mom
There are two kinds of tragic backstories in One Piece. The first involves many layers of sadness and this type of backstory usually tends to humanize the character in question. E.g: Brook’s backstory.
The other kind is where the recipient is painted as a monster; Big Mom is a good example of this. Her true origins are unknown, yet they seem extremely mysterious. All we know about her is her tragic and sad past with Mother Carmel and the Sheep House orphanage.
5 Unknown: Akainu
A grand villain such as Akainu needs no backstory to highlight his villainy. In all likelihood, the audience will get nothing worthy of sympathy regarding Akainu and his past; that would just conflict with the Fleet Admiral's depiction so far.
If anything, it is more likely that One Piece will present some sort of backstory that further fuels the hate fans have for Akainu. That seems to be the role that Oda intends for him.
4 Tragic Backstory: Senior Pink
Senior Pink’s infamous past is a prime example of Oda’s amazing skills as a mangaka and storyteller. He, a seemingly irrelevant minor villain, became a fan-favorite antagonist after the reveal of his short, few panels-long backstory.
This also proves that if Oda gave most of his villains a tragic backstory, they’ll cease to be villains in the fans’ eyes. His skills are simply that terrifying.
3 Unknown: Blackbeard
Blackbeard, along with his crew, is another major hurdle the Straw Hats will have to face sooner or later. Blackbeard is one of the few characters that Luffy shows visible disgust to.
At the moment, everything about Blackbeard and his past remains a mystery. Audiences have only been shown a short panel about his youth, and that was the extent of it. More info will most likely be made available later on in the series.
2 Tragic Backstory: Doflamingo
Doflamingo’s flashbacks serve as both a means to humanize and de-humanize him. His fall from grace, retaliation against his father, and his debut to villainy were perfectly sequenced to highlight his progressive transformation from a rage-fueled child to a rage-fueled adult.
The events of Dressrosa are most likely not the end of his story either. The return of this Heavenly Demon cannot come soon enough, and it will likely be incredible.
1 Unknown: Kaido
Out of all the Yonko, Kaido is undoubtedly the one audiences know the least about. Fans are in the dark about anything concerning him besides the fact that he used to be a member of the Rocks Pirates. The story has focused almost exclusively on Kaido's time in Wano Country, while also establishing the character's goal to start a huge war.
With that being said, One Piece will most likely provide the answers fans seek sometime soon in the currently ongoing Wano Arc.
