@Captain-M Rebecca is one of my favourite character in Dressrosa and how well Oda just handled her was spectacular too but it's just sad that the vast majority of readers fails to realize her worth because she is seen wearing a pretty revealing and call her a "damsel in a distress" as she isn't shown killing some big bads in the arc which just shows the reading comprehension of these people but I will try to fill in every information I could about her and properly explain her super hated outfit and her entire characterization from scratch.
The bikini armour that she wears is often seen as negative and misunderstood as a representation of oversexualisation. What is she wearing though and why is she wearing it? To begin with, she is a pacifist and yet competing in the Colosseum which itself comes straight from the Romans (so we can expect a lot of references towards Roman culture). Her being a pacifist impacts her choices on both how she fights which in turn affects her choice in appropriate armour. Her fighting style is based entirely on evading, disarming, countering and controlling the attackers body weight. Knowing this, in practicality what she needs is light armour that allows her to be as flexible as she can; the armour itself doesn't need to be strong as it should never be in the position where she needs to actually rely on it.
This gives us the general outline of what she needs from her armour. She's in the Colosseum as a gladiator which was strangely one of the least sexist places, in function, that the Romans had. Both men and women competed (though not often in a mixed setting as Oda has written) for money, glory and better lives. we'll look at her choices in her armour that works on the same idea as Acilia but the representation is different.
To begin with there's her helmet. This is a gold (traditionally would've been iron with a silver or gold gilting) Late Roman ridge helmet with a red plume. The existence of the plume on the helmet represents status, or rank and would've been exclusively for centurions or higher ranking military members. Next is her greaves; the shin guards which were also considered a status symbol within Roman culture (we find a good number of people buried with a single greave that seems to support this). Her weapon of choice is a gilted long sword which seems to be more of a connection between to the Spanish cultural aspects that's been injected into Dressrosa which seems to serve the story telling of Don Quixote (both Doffy and the actual story of Don Quixote).
Her chest piece is a form of lorica squamata which is a type of scale mail armour famously used by the Romans which was also generally made out of iron but you can find depictions of emperors and higher officials wearing similarly gold/silver gilted scale mail. She also wears a gold cingulum or baltea (which was more common with centurions who would wear lorica segmentata, or segmented armour) which was a a piece of armour which worked as an apron-like thing which protected the genitals; the more high status you were the more often this would change from leather straps (which most of the other gladiators are seen in) to gilted scale metal armour. Then there's her paludamentum (the cloak/cape) which seemed reserved for military commanders. After the reign of Augustus (the guy responsible for the English August month's name) it became restricted to just the emperor. The fact that it's blue is also a representation of rank, as blue was historically kept for higher classes as it's one of the most expensive and difficult dye's to create from natural resources (blue is one of the rarest colours in nature).
Her entire outfit is a recognition of her former royalty and her presence both in the Colosseum as well as the fact that it was a choice that she could make as any other gladiator could, is a reference of how Doffy was diminishing the worth of the previous Royals culture as well as the royalty itself. This would've been in part what could make the crowd against Rebecca as not only was she seen as from a hateful royal family line, but also the fact that she's holding onto these cultural aspects which used to seperate the common person from the upper classes. You can see this difference between Rebecca and Acilia; Acilia wears simple greaves, simple leather strips, and an iron helmet without a plume. She does wear a paludamentum which references high status but this is likely taken straight from her historical counterpart; there existed a real gladiatrix called Achillia which is seen depicted with one which seems to be a "cosplay" female version of the warrior Achillies. There's a stone carving of her fighting against a representation of the the mythical Amazonians.
Had to get all that off my chest lol.
How did Rebecca become the person she was when we see her at the Colosseum? To begin with she was born in secrecy from a princess and a military commander after spending years and years fighting against his own violent nature and history. She lived in general happiness until Doffy appeared and one of his family murdered her mother. Her father, was literally objectified, removing all memory, love and worth that she had for him. However, he was the one to now raise her as a stranger. Through his shame for his past violent nature he made an effort to protect her from this type of life; feeling he was not worthy of even touching his own daughter; yet had to carry her mothers corpse to her unable to properly grieve himself as he was a stranger to his daughter and he had to put her first. This is where men generally become emotionally objectified; he had to somehow put those things to the side and look forward. Even at the end of the story he was going to remove himself from her life for her sake.
So she was essentially raised as an orphan with emphasis put on pacifism; yet had to learn to protect herself and dodge because of the dangerous times she was living in. She was against violence from this teaching from her father and despite this great limitation they both put on her she had the confidence adn strength to enter the Colosseum in order to get to Doffy. She was willing to go against her values and morals, which would emotionally hurt her, in order to take out Doffy and save both her country and herself and Kyros. Her motivating factor being that she loved the toy soldier like a father (because despite the literal objectification of him, he behaved and treated her like she was his child). Her dream being to create a peaceful environment where she could live with what she thought was her found father figure.
Rebecca herself being a kind person who put others before herself (which can be seen with her giving up food to Luffy and how the old gladiators felt about her) which can also be seen in her grandfather. What would normally be a story where she would be objectified to a simply damsel in distress became a story about fighting against tyranny with pacifism where she attempted to right the wrongs of the past. Oda doesn't shy away from the more difficult aspects of the pacifist ideology either; he will put her in positions where it seems like the only option is violence, he temps her with it and certain characters even take away her will and attempt to force her into it. She's a representation of inherited trauma, fighting against the publics view's of her as their beliefs are manipulated by cruel people through political, cultural and even magical manipulations of what reality is. Despite this, she remains a virtuous at her own expense, she stood up as a symbol of justice through non-violence. Her compassion for others and the courage she has to stand up to these things keep her set on her goal despite the horrors, both physically and mentally, that she's put through in order to make her falter.
There's a saying I like that comes with the following bit: "It's better to be a soldier in a garden, than a gardener at war." Oda has recognised this aspect of pacifism mixed with ability to defend and offers a more nuanced take. When she finally meets the murderer of her mother, in a garden of sunflowers, her pacifist ideology hits a wall. She is forced to wrestle with her own morals and ideology in order to get past this obstacle. Oda offers a solution where she can keep true to herself; by understanding that she doesn't need to and that she can literally rely on a soldier in a garden rather than become the soldier herself. There's a problem that a lot of ideologies get into that Oda recognises; they're short sighted and often don't apply theory of mind or group outcomes. War exists and so do pacifists, but reality shows that people are neither good or bad and that they're simply grey blobs consisting of good and bad motivations. When we can't do something, for whatever reason, then we have to rely on others. In Oda's fashion it's more about knowing what to pass down to following generations. Kyros has went a bit too hard in pushing for pacifism from the shame of his own violent past and through that we get the recognition that it is a virtuous intention but the ideology is incomplete without a moderating factor from the reality of life. It's a recognition that pure pacifism like Rebecca's is a nice thing to believe in but functionally it puts the responsibility of action on others; and when we're young children that responsibility often lands on our parents as they try to guide us through life. She, herself, is an inverse of Doffy. While Doffy went through many of the same issues that she did, it's how we're guided through life by our gaurdians that molds us into who we are. Where Doffy was groomed into being a murderous being who's goal is chaos and destruction, Rebecca has been groomed for peace and freedom. Her true motivation, is to simply live in peace with her father.
Don't misunderstand me here; I don't believe that Rebecca is stupid or unaware that pacifism like that requires relying on others to make up for it's flaws. I think that's she's courageous and steadfast in her beliefs and the only time we really see her falter is when it comes to her being face to face with her mothers murderer. This almost worked too but when it comes to our most weakened states and we're encouraged to do things against our own morals and beliefs; that's when we should be looking for support because we can't do everything by ourselves, while we also can't expect others to do everything for us. Kyros appearing and fighting Diamante wasn't him saving a damsel in distress (stereotype, she was definitely in distress); it was him appearing to do the things she couldn't so she didn't have to go against her own beliefs and morals. He helped her back to her feet and dirtied his hands so she didn't need to (which I think we can agree, children shouldn't kill people). A recognition that his actions are hurtful, and that he wants to protect his child from them. This also mirrors what we had with Fisher Tiger; Kyros had that violence in him in the same way that Tiger had that racism in him and both shared the recognition that it was wrong. Both understood they couldn't do anything about the fact it was in them, but understood the importance of not sharing that with the future generations. Violence, is unfortunately a reality of life, unlike racism which is a social construct.
Most storytelling would see Rebecca reduced to a sex object or a damsel in distress. Oda, on the other hand, creates a story that is always recognising Rebecca's own agency and her own choices; from her choice of what she's wearing to her actions and motivations. Despite the pacifist ideology, Oda gives her plenty of challenges that she herself needs to fight against and where she can't she relies on others. This has been taught throughout One Piece, all the way back to Luffy fighting Arlong and proudly stating he needs to rely on others to survive. This is not weakness, this is reality; if Rebecca was weak then she wouldn't have been able to hold onto her beliefs in the face of such brutal testing. Even when the characters in the story remove her agency (Doffy controlling her) she retains it as a character screaming out about it. At the end of the story, she also showcases her emotional stoicism that she got from her father and sacrifices what she wants thinking that she was doing it for him. The whole goal and dream that she was fighting for from the beginning, she was willing to give up on because she believed it was something he wanted. That is insanely strong conviction to attempt to sacrifice so much for anothers sake. That scene with Luffy at the window asking her what she wants always gets me. I hate that she gets objectified and reduced to her body and gender; especially under the false idea that the people saying this are fighting against sexism, when they're the one's reducing her to that perception.
Woosh! finally done