The world of One Piece is jam-packed with iconic heavy-hitters, from heroic pirates like Monkey D. Luffy or Shanks, to evil pirates like Kaido or Big Mom, and even corrupt Marine officials, like the three Admirals. Needless to say, Eiichiro Oda has introduced countless powerful characters throughout the original manga’s twenty-eight-year run.

Curiously enough, however, some of the strongest combatants in One Piece don’t even exist in canon, seeing as Toei Animation had to create multiple anime-only characters that ended up being surprisingly powerful. With over fifteen different filler arcs, there’s a naturally large cast of characters to choose from, but the following eight are the most remarkable examples of this fascinating phenomenon.

Caroline

The Substitute Queen Of Kamabakka Kingdom

  • Debut: Episode 454
  • Arc: Straw Hat's Separation Serial Arc

Some One Piece fans may take a look at Caroline, the substitute queen of Kamabakka Kingdom whenever Emporio Ivankov is absent, and assume that they’re actually a canon character. In reality, they were originally created for the anime, as they didn’t appear in the cover story that showed what Sanji was doing in the land of the Okamas during the time skip.

As one would expect from someone with such a high-ranking position, Caroline is a skilled fighter and a master of the eccentric but effective fighting style known as Newkama Kenpo. As a matter of fact, Caroline was the first of the ninety-nine Newkama Kenpo masters Sanji had to defeat in order to obtain ninety-nine Attack Cuisine recipes during his training.

Largo

Wields The Powers Of A Surprisingly Versatile Devil Fruit

  • Debut: Episode 426
  • Arc: Little East Blue Arc

At first glance, Largo may not seem all that powerful. After all, he’s the captain of a relatively small pirate crew called the Amigo Pirates, and he’s the main antagonist of a run-of-the-mill filler arc called the Little East Blue Arc. Nevertheless, the secret to his strength lies in his Devil Fruit.

Largo ate the Ami Ami no Mi, which allows him to turn any substance he consumes into nets, including boiling water, fire and barbed wire. It’s a surprisingly versatile ability that allowed him to defeat and capture Luffy, Zoro, and Sanji in their initial encounter. On top of that, he’s able to morph entire parts of his body into nets and absorb strong physical attacks from his opponents.

Breed

This Cruel Beast Tamer Hides A Secret Power-Up

  • Debut: Episode 625
  • Arc: Caesar Retrieval Arc

Breed, the main antagonist of the Caesar Retrieval Arc, is a cruel and sadistic beast-taming pirate who wields the powers of the Peto Peto no Mi, a non-canon Devil Fruit that he uses to create green collars that will turn any living being who wears them into his “pets”, meaning that they’re forced to follow every single one of his malicious orders.

Naturally, having full control of a large army of strong marine creatures that follow his orders (which includes Kung-Fu Dugongs and a giant Kraken) is already quite dangerous, but it’s worth pointing out that Breed’s Devil Fruit hides a very useful secret ability. If he wears one of his own collars, he can bring out the full extent of his power and turn into a massive, hulking beast. While in this form, he was able to face both Luffy and Law by himself.

Don Accino

The Patriarch Of The Accino Family Ate A Powerful Devil Fruit

  • Debut: Episode 326
  • Arc: Ice Hunter Arc

The Ice Hunter Arc is one of the most interesting and distinct filler arcs in the One Piece anime, mainly because its main antagonists, the Accino Family, are bounty hunters instead of pirates or marines. Sitting at the top of this family’s hierarchy is their patriarch, the one and only Don Accino.

He is a bulky, skilled, and temperamental man who ate one of the absolute strongest non-canon Devil Fruits: the Atsu Atsu no Mi. Its powers are reminiscent of the canon Netsu Netsu no Mi, as it allows Don Accino to increase his own temperature to an absurd degree: the angrier he is, the hotter his body becomes. And that’s not all, because he can also create balls of heat that he can throw at his targets and use as ranged projectiles. Despite Don Accino's immense power, Luffy was eventually able to defeat Don Accino and recover his crew’s stolen flag after a long and challenging battle.

Bill

The Leader Of The Silver Pirate Alliance Is A True Force To Be Reckoned With

  • Debut: Episode 746
  • Arc: Silver Mine Arc

Despite his seemingly mundane appearance and unthreatening name, Bill is actually one of the strongest non-canon characters in the entire One Piece anime. After all, he’s both the leader of a massive alliance between many pirate crews called the Silver Pirate Alliance and the main antagonist of the Silver Mine Arc.

Bill is not only a confident and charismatic pirate captain who’s admired by his own subordinates, but he also ate a weird but effective Devil Fruit called the Gutsu Gutsu no Mi. It basically turned him into a living furnace that can consume and melt metals to create weapons, shoot scorching ore and even coat his entire body with silver. If it wasn’t for Bartolomeo and the durable barriers of his Bari Bari no Mi, Luffy would never have been able to defeat Bill.

Mad Treasure

He’s Strong, Unpredictable, And Ate A Powerful Devil Fruit

  • Debut: Heart of Gold (TV Special)
  • Arc: Heart of Gold Arc

Like most antagonists from filler arcs that take place after the time skip, Mad Treasure is a surprisingly powerful character that’s on the same level as some of the series’ strongest canonical combatants. He’s an infamous treasure hunter and the captain of the Treasure Pirates, a crew that works for Gild Tesoro, who is, in turn, one of the most powerful villains who originates from a One Piece movie.

Needless to say, Mad Treasure is notorious for his unhinged personality and his impressive fighting skills, which go perfectly with his Devil Fruit, the Jara Jara no Mi. With its powers, he can summon a seemingly endless number of chains, which he can use both for offense (by wielding them as whips) and defense (by covering his body with them). Mad Treasure was a formidable opponent who was able to go toe-to-toe against CP0 agents and even capture most of the Straw Hat Pirates with his chains, until Luffy eventually managed to break through his defenses and finally knock him out.

All-Hunt Grount

A Heroic Marine Captain Who Ate A Mysterious Zoan Devil Fruit

  • Debut: Episode 780
  • Arc: Marine Rookie Arc

All-Hunt Grount is one of the most fascinating One Piece characters that was created exclusively for the anime. Due to his design, personality, mannerisms and voice actor, he feels like a parody of traditional shōnen anime protagonists, which is perfectly reflected in his fierce rivalry with Monkey D. Luffy. As a Marine Captain who was trained by Kuzan, Grount is an experienced and intelligent fighter, but the most notorious part of his skill set is the unnamed Zoan-Type Devil Fruit that he ate.

He can transform his left arm into the limb of a hulking beast with sharp claws and red fur, with the only downside being the fact that he often loses control of his Zoan powers. This arm grants him immense strength that he used to fight mano-a-mano against Luffy and even though he was eventually defeated by the captain of the Straw Hat Pirates, he was able to gain control over his mysterious powers at the very end. If, at some point, Grount manages to master his full Zoan transformation, he may become one of the strongest Marine Captains in the One Piece world.

Byrnndi World

A Terrifying Pirate Captain With A Practical Devil Fruit And Mastery Of Armament Haki

  • Debut: 3D2Y: Overcome Ace's Death! Luffy's Vow to his Friends (TV Special)
  • Arc: 3D2Y Arc

Out of all the powerful and dangerous pirate captains that Luffy confronted in non-canon material, Byrnndi World, the main antagonist of the 3D2Y TV Special, is definitely the strongest. For starters, he’s a legendary pirate who has been active for over thirty years, commands a pirate crew of efficient fighters like Gairam and Sebastian, and was even imprisoned in Level 6 of Impel Down until he escaped during the breakout caused by Luffy himself.

But World would never have been able to get so far in this world if it weren’t for his impressive combination of powers and abilities. He ate the Moa Moa no Mi, which allows him to enlarge any object he touches (like weapons or projectiles), he has mastered Armament Haki (and can coat his entire body with it), and he can even use some Rokushiki techniques, like Soru and Geppo. Very few filler villains are depicted as true threats, and Luffy usually doesn’t have a hard time defeating them, but Byrnndi World is a notorious exception: defeating him took the young pirate a lot of effort, which is especially impressive, considering he fought him in the middle of his arduous two-year-long training.

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One Piece
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Release Date
October 20, 1999
Network
Fuji TV
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  • Cast Placeholder Image
    Mayumi Tanaka
    Monkey D. Luffy (voice)
  • Cast Placeholder Image
    Kazuya Nakai
    Roronoa Zoro (voice)

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One Piece is a Japanese manga written and illustrated by Eiichiro Oda. The series follows protagonist Monkey D. Luffy and his Straw Hat Pirate crew as they explore the Grand Line to find the King of the Pirates' ultimate treasure, the One Piece, in order to become the next king. The manga's popularity helped it spin off into a larger media franchise, including an anime with more than 1,000 episodes.

Number of Episodes
1122
Streaming Service(s)
Crunchyroll, Netflix, Hulu, Pluto TV
MyAnimeList Score
8.72