One Piece is a fantasy/adventure series with tons to explore. However, as vast of a world as it is, it's not exactly an empty template without some cultural texture. Embedded within the series' history is a long line of war, nobility, and politics that has crafted the various kingdoms the Straw Hats now explore.
With that territory comes the various rulers and authority that go with them, with each one seemingly as culturally distinct as the environments they nurture. However, not all rulers are made equal (let alone wanted to be treated as equal), as One Piece has seen an entire spectrum between selfless, charitable kings and queens to some of the most selfish and corrupt nobility. This list will be looking at the worst and best crowns, as it runs down the series' best and worst rulers.
10 Worst: Saint Charloss
Starting off this list is a Celestial Dragon that does a great job of setting the scummy tone to expect from all Celestial Dragons. Within the larger history of One Piece, the Celestial Dragons are the ancestors of the original kings and queens that banded together to form the World Government but abandoned their own kingdoms to live in their hoarded luxury.
Saint Charloss is a fine example of what that wealth and power can do to a person, as he perfectly exemplifies the spoiled childishness embedded in the nobles as well as the quick-tempered malevolence that goes with slightly inconveniencing them.
9 Best: Gan Fall
The term "God" has a weird stance in the One Piece world. While many characters surely exemplify some belief in both mythical beings and a higher order, one land, in particular, is willing to grant all the power and prestige of the title to their own ruler. Within Skypeia, the land resembles an early, colonial setting where the religious sect takes dominance over the country's politics.
That religious sect, oddly enough, isn't exactly guided by the wisest or most benevolent ruler but whoever appears strongest. And while Eneru certainly displayed this identity in a poor light, his corruption is only greatly juxtaposed against the incredibly caring and benevolent legacy of the nation's previous god, Gan Fall, who dedicated his life to patrolling the skies and helping travelers after he was usurped.
8 Worst: Stelly
Stelly is a fresh entry to the long line of the nobility of One Piece's world, and he's made a fine impression of what kind of ruler he is. As a young boy, he was literally adopted as the more promising, agreeable replacement to Sabo, when the young revolutionary to be ran away from home.
Having taken hold of the household upon Sabo's seeming death, Stelly would marry into the Goa Kingdom's castle and subtly rise to become its ruler after the totally mysterious deaths of its past rulers. As such, the smirky kid that everyone wanted to punch upon his introduction now has a seat at the Reverie, and that really says a lot of how politics works in One Piece.
7 Best: Dalton
Dalton isn't the most direct, linear definition of a ruler. He wasn't brought up from a noble family nor is he built on a political platform. He was once just the head of the guard of the Drum Kingdom and a servant to its previous king, Wapol. Despite having to protect and serve a literal eating machine, Dalton was a kind man who patrolled his country's cold streets and offered a kind hand to its citizens.
After Wapol's sudden and resounding departure from the kingdom's throne (Thanks, Luffy!), no one else could better take the seat and drastically change the tone of the country's rule than its gentle, everyman.
6 Worst: Donquixote Doflamingo
At the other side of the caring spectrum, Donquixote Doflamingo ruled Dressroas with iron marionette strings, as he claimed his throne through a dubious, murderous conspiracy and later ruled the country through further secretive and manipulative means. He made Dressroas his base of operations for all his pirating activities and dedicated much of its functions to either producing SMILE fruits for Kaido or trading and shipping weapons to various wars across the world.
If there was any opposition to his less-than-kind rule, Doflamingo would either sentence them to fight endlessly in the Corrida Colosseum or, better yet, transform them into a toy to be forgotten yet subjugated by their very own families.
5 Best: Nefertari Cobra and Vivi
In direct contrast to Doflamingo's reign is the selfless and caring hands of the only family of the world nobles to not abandon their kingdom. Where Dressrosa was a poor kingdom that was brought great prosperity thanks to the shady dealings of its new king, Alabasta was a poor kingdom that was sustained through the sincerity and sense of union from its king, Nefertari Cobra.
Though that benevolence would be contorted and challenged by the slandering activities of Sir Crocodile, Princess Vivi wouldn't give up on the kingdom and risked her life to bring the truth to her people, even sacrificing the adventure of a lifetime to serve Alabasta.
4 Worst: Big Mom
Just looking at Big Mom and her entire kingdom is enough to understand what type of ruler she is. Charlotte Linlin and the creamy foundation of Whole Cake Island just scream excess and indulgence to the viewer. Having raided or shaken down other kingdoms for their resources, Big Mom either dedicates them to building impractical homes for people or just hoarding and consuming them for herself.
However, that's just a quirk to her greater evils, such as rampaging across her kingdom whenever she has a tantrum, killing anyone who stands in her way and taking portions of people's souls/lifespans as tax for living in her kingdom. The diversity of Whole Cake Island itself is not so much of a melting point, as it is a collector's set for a giant, spoiled child.
3 Best: Otohime
Fishman Island hasn't exactly been at the top of the food chain. Due to its people's appearances, the land is often relegated to the sidelines of world politics, and its people are either segregated from the rest of society or made into a commodity for slave traders and the nobility.
As terrible as humanity has been overall to them, one mermaid never gave up hope. Queen Otohime is a pillar of unity and peace that ceaselessly worked to improve human-fishman relations and to campaign for the improvement of fishman life overall. Trying to create change from a soapbox and not a throne, Otohime is one to have unbiased love for all beings.
2 Worst: Kurozumi Orochi
The newest face overall on this list, Kurozomi Orochi is the greedy, gluttonous shogun of Wano. An ancestor of a long trying family in Wano's lineage, Orochi's entire being is built on conspiracy and entitled ideals. He started his campaign as the thieving aid to Yasuie. However, after getting a little close to Oden and having gained his favor through his various negligent absences in the kingdom, Orochi rose to power as an intermediary shogun after the not-so-mysterious death of the previous shogun.
While on the throne, Orochi secured his power by enlisting the aid of Kaido, giving the rising pirate land, resources, and labor to manufacture weapons and pollute Wano's water and soil. Hoarding all the actual edible stuff for himself, Orochi sits on a comfortable throne suffocating a dying country.
1 Best: Riku Doldo III
King Riku of Dressrosa is a man to put everything and everyone before himself. This has come to mean giving even its most infamous barbarian an opportunity within his guard, providing aid to other kingdoms while his own country still struggles, and refusing to raise a hand against the ensuing threat of Donquixote Doflamingo.
Even after losing his throne to Doflamingo and hiding his shame, Riku still fought for Dressrosa by competing in the Corrida Colosseum for the Flame Flame fruit. Above all else, Riku Doldo believes in the power of caring and peace to guide and serve his people. While they are not exactly the most prosperous ideals, they are allowing him and his kingdom to live in good faith and conscience which can go a long way in One Piece's changing, political landscape.