Monkey D. Luffy is one of the main characters in the One Piece franchise. He strives to become the Pirate King and freely traverse through the seas.

Being in the journey of a pirate king is tough, especially when there are so many villains that one has to face. Luffy's battle with these opponents is off the chart.

Here are some of Luffy's worst opponents he had to face so far that had him go over his limits.

1) Arlong

one piece smoker

Arlong was one of the strongest opponents that Luffy had to face before he ventured into the Grand Line. His cunning tactics and overwhelming strength nearly drove Luffy into a corner. Being a devil fruit user, Luffy was vulnerable when he was close to water surfaces, whereas Arlong can freely traverse and battle in the water at double the speed and strength.

The arc was centered around Nami and her hometown called Cocoyasi village. Cocoyasi town was being governed by Arlong, who was an overbearing sea dweller.

Arlong was extremely overconfident about his physique as a fish-man. He guaranteed that he would defeat Luffy and secure his victory effortlessly. However, as the battle began, Arlong was unmistakably frantic at Luffy's shenanigans, and could hardly imagine how Luffy was evading the greater part of his assaults. After battling in a room filled with maps, Luffy began to fight seriously.

Luffy annihilates the whole stay with his assaults, to facilitate the enduring of Nami. He at last beat Arlong with his assault technique named Gomu Gomu No Battle Axe, which cut down the whole Arlong Park in half.

2) Smoker

one piece smoker

Luffy's first appropriate defeat came in the hand of Smoker, who was a Marine Captain during the Logue Town Arc. Owning a Logia type devil fruit called Moku Moku no mi ( Smoke-Smoke), his body was made up of smoke. The power of the devil fruit gave him the full authority for controlling smoke. 

Luffy and Smoker have an energetically opposing relationship that goes back and forth all through the whole of the series. Smoker's essential objective was to catch Luffy. When Smoker met Luffy for the first time, he had him overwhelmed with using just a solitary punch.

The fight between the two wrapped up quickly in favor of Smoker. He was ready to arrest Luffy and bring him to prison. In the nick of time, Monkey D. Dragon appeared out of nowhere and saved him. If he hadn't done that, Luffy's journey of becoming a Pirate King would have been over.

This recites that Smoker was one of the toughest adversaries that Luffy had to face before he ventured into the Grand Line.

3) Crocodile

one piece smoker

Luffy's first enormous hurdle came into the Grand Line against one of the Seven Warlords of the Sea and the pioneer of Baroque Works, Sir Crocodile. As a privateer, Crocodile was known to be violent and fierce, having cruised the oceans of the New World.

Owning a logia type devil fruit called Suna- Suna no mi (Sand-Sand), Crocodile's body was also immune to any attacks. The power of the devil fruit gives him full control of controlling sand.

The arc was centered around Vivi and the Alabasta Kingdom. Sir Crocodile governed the Alabasta Kingdom.

With his Sand-Sand Fruit powers, he was a colossal adversary for Luffy, whom he devastated with his powerful arsenals of attacks that nearly drove Luffy to death. Luffy lost to Crocodile twice. His first defeat came when a hook skewered him and almost led to suffocating in the sand. In contrast, the subsequent battle left him dried out.

In the wake of losing twice, Luffy figured out how to defeat Crocodile for the last time by discovering that he required water to crush sand.

He finished his battle with Crocodile underground the Alabasta ruins with Gomu Gomu no Storm using his blood as a medium to water.

4) God Enel

one piece smoker

Enel was thought to be a godly character when he made his debut in the Skypiea Arc. He possessed a unique kind of Logia devil fruit called Goro Goro no Mi, which allowed him to produce, control, and convert into lightning at will.

As God Enel overcame every adversary with ease in his way to conquer, it made him clear to see that Luffy was on the other level. The assistance of him being elastic and Enel being lighting played a significant consideration on the plot. This led to the confrontation that set two common adversaries in opposition to one another.

As the battle ensued, Enel's every attack deemed non-effective to Luffy, so he chose to fight at close combat using a trident. Similarly, Luffy's every blow was evaded by Enel, so the outcome was a draw. This forced Luffy to think of a strategy to overcome the situation. 

However, Luffy, unavoidably, lost the primary fight with Enel and needed to re-battle him again to beat him and protect Skypiea from the impending danger.

As the battle drew closer, Luffy beat Enel by contorting his golden ball attached to his hand directly into Enel's body, sending him colliding with the Bell and overcoming him.

5) Rob Lucci

one piece rob lucci

Luffy's fight against Rob Lucci was clarified as one of the most thrilling benchmarks of the One Piece franchise. It was an exciting fight that was known to be in the top 10 battle list of the series. Rob Lucci consumed the Neko Neko no Mi, Model: Leopard, a Zoan-type Devil Fruit, which permitted him to shapeshift into a full-grown Leopard.

The battle among Luffy and Rob Lucci in Water 7 and Enies Lobby made a standpoint in the series, which caused a significant trademark. The first trademark was the mayhem and the stakes that it brought when both of them pitted against each other at full scale and desperate to overcome the other.

Subsequently, the second trademark was putting a challenge to the World Government as an announcement of war to the whole world. 

As his battle sued in Water 7, Lucci devastated Luffy without breaking a sweat with his unique abilities. Luffy's fight against Lucci constrained him to go over his limits to learn new techniques. Luffy managed to develop two new techniques called Gear Second and Gear Third, to stay aware of CP-9 and save Robin from their grasp.

Even in his Gear Second and Gear Third abilities, Luffy had trouble beating the pioneer of the CP9. However, Luffy defeated Rob Lucci with his determination, will power, and pure brute strength.

6) Gekko Moria

one piece smoker

Gekko Moria was the commander of the Thriller Bark Pirates and a previous Warlord of the sea, who resided on the biggest boat called the Thriller Bark. Moria became an adversary of Monkey D. Luffy, who assumed a crucial job in vanquishing him altogether with his military of zombies in the Thriller Bark Arc.

At Thriller Bark, he disclosed to Luffy that with his present strength, he would lose his crew sooner or later. 

Moria ate the Kage Kage no Mi, a Paramecia type Devil Fruit that permitted him to manifest, steal and control shadows. Due to this devil fruit, Moria can assemble his zombie armed force by discarding living creatures of their shadows and embedding them into dead bodies.

Gecko Moria and Luffy conflicted with one another back in the Thriller Bark. In the wake of having his shadow taken by Moriah utilizing his Shadow-Shadow devil fruit, Luffy needed to fall back as to embed himself by occupying the shadows of others to battle Moria.

This saw the presentation of nightmare Luffy, a bulkier and impressive version of Luffy. However, the Warlord of the sea also answered with his strength by utilizing his Shadow Asgard technique to make himself tremendously large.

Luffy saw this as a potential benefit and defeated Moria by using an assault technique called Gomu Gomu no Gigant Jet Shell. This led to Moria's defeat, which made Luffy fight over his limits and nearly drove him into a corner.

7) Magellan

one piece magellan

While trying to save his sibling Portgas D. Ace, Luffy broke into the best-known jail in the realm of One Piece called the Impel Down. With Ace nearly being inside his scope, Luffy's way was obstructed by the undefeated Warden of Impel Down, Magellan.

Magellan ate the Doku Doku no Mi devil fruit, which allowed him to generate and manipulate poison. Because of his Doku Doku no Mi power, Magellan had the option to overcome Luffy within moments and subdue him with ease.

Luffy's battle against Magellan in Impel Down runs contrary to the natural order of things from multiple points of view. The two go back and forth in terms of durability; however, Magellan rapidly closes the fight when he covers Luffy with his Hydra poison.

Magellan's Venom-Venom Devil Fruit is a potent kind of poison where many criminals that have faced him before haven't survived. But, Luffy was an exemption. His sheer willpower and tenacity made him overcome the biggest hurdle of his life that drove him into the brink of death with the help of Ivankov. 

Magellan was the first adversary that Luffy cannot defeat with his abilities. His sheer touch makes the body of an enemy nimble and soaked with poison.

No matter what Luffy came up with, Magellan just overwhelmed Luffy in both strength and techniques.

8) Caeser Clown

one piece smoker

Caeser was a scientist and a former colleague of Vegapunk. He was also the preeminent expert for researching chemical weapons of mass destruction. He ate the Gasu Gasu no Mi devil fruit, which allowed him to control, manifest, and transform him into a gas at will. He was also the collaborator for Kaido and Doflamingo to provide them with SMILE Devil fruit.

Caesar postured a new hurdle for Luffy because he possessed and displayed a vast number of varied skills at his arsenal. In terms of brute strength, Luffy's strategies were more remarkable than Caesar's. However, he was able to safeguard himself in some exceptionally flexible manner that caught Luffy by astonishment.

Caesar's greatest stunt was that he was able to control and manifest oxygen at will. He utilized these techniques on Luffy to choke him out to the point of rendering him unconscious. Ceaser laid many traps and strategies for Luffy to make his fight with him easier and to defeat the latter with ease.

However, when he got his rematch against Caesar, he defeated him with an unorthodox technique called Gomu Gomu no Grizzly Magnum and cathartically got his vengeance. As a logia type user, Ceaser's devil fruit was troublesome and can render the oxygen around the surroundings at will, which was the primary source for all living beings to survive.

Caesar was one of the most dangerous adversaries, which gave Luffy some trouble after his training for two years.

9) Doflamingo

one piece smoker

Doflamingo was known as the captain of the Donquixoite Pirates, one of the seven warlords of the sea, an underworld broker, and one of the most trusted collaborators for Kaido. He ate the Ito Ito no mi devil fruit, which permitted him to control and manifest strings at will.

This battle was also clarified as one of the top 10 battles of the One Piece franchise. Many new significant trademarks were introduced into this arc with several new characters. The first trademark was the initiation of Gear Fourth, along with the fantastic battle between Luffy vs.Doflamingo.

Doflamingo ended up being more robust than anyone has ever envisioned. Every time he took damage, he healed himself by utilizing his devil fruit powers.

The other trademark was that Doflamingo also showed the awakening of the devil fruit, which was the next and last phase. He used his devil fruit's awakening to affiliate the whole surroundings near him to change them into strings and used them to assault Luffy. Doflamingo also possessed the same type of Haki that Luffy possessed.

Luffy fought all out with Doflamingo from the start and was unable even to touch or harm him. He gave his all-out by using every technique that he had in his arsenal. He then showed the next level of his devil fruit powers by initiating a Gear Fourth, which he developed while he was training with Rayleigh on Ruskiana.

Even with his full strength, Luffy was barely able to defeat Doflamingo in his first turn. He was exhausted from the prolonged use of his Gear Fourth ability that needed Haki and needed to recharge himself.

During the second round, he defeated Doflamingo by using a Gear Fourth technique called King Kong Gun and thus ending his reign over Dressrosa.

10) Katakuri

one piece katakuri

Much the same as other significant fights of Luffy, he battled Katakuri a few times before he figured out how to defeat him. This matchup between Luffy and Katakuri was declared to be one of the best battles. This situation was an enormous hurdle for Luffy and his crew, as he needed to shield his companions from the Yonko Commander Charlotte Katakuri, who had an abundance of 1,057,000,000 Berries as well as the rest of the Big Mom pirates.

Katakuri ate a special type of paramecia devil fruit called Mochi Mochi no Mi that allowed him to control, manifest, and transform into a mochi at will.

The two conflicted at the Tea Party first, where Luffy was saved by Jimbei, from the latter's overwhelming strength. Afterward, in the Mirror-World, Luffy and Katakuri battled again, and the Sweet Commander demonstrated his predominance over Luffy, pushing him to leave the battlefield until his Haki returned.

Luffy was bulldozed many times in this fight but unable to overcome the sweet commander. Luffy used all of the techniques that he possessed in his arsenal but unable to land a single hit until he grasped how Katakuri fought.

By learning the trick of Katakuri's Haki, which allowed the latter to see in the future to avoid attacks and to oversee what was going to happen, Luffy tried to do so as well but failed many times until he was able to realize the next form of Haki finally.

By going back and forth through the battle, Luffy prevailed Katakuri with his sheer willpower and perseverance. He defeated Katakuri by using the Gear fourth technique called Snake Man.

11) Kaido

one piece smoker

The showdown among Luffy and Kaido was one of the latest fights to occur in the series and is set during the Straw Hat Pirates' time in Wano. There were plenty of stakes riding on this fight, and although Luffy may have had the option to defeat Kaido under various conditions, he was excessively blinded by anger to consider his battle plan appropriately.

Kaido ate a legendary Zoan type devil fruit that allowed him to shapeshift from his humanoid structure into an enormous blue eastern mythical serpent. In his winged serpent structure, Kaido can fly and have mists of clouds show up around him.

Monkey D. Luffy clashed against one of the Four Emperors of the Sea, Kaido, in the Wano Country. Even though the original arrangement was to bring Kaido down at Onigashima, Luffy first engaged the Yonko in Kuri, hitting him with everything that he had in his arsenal without a moment's delay.

Shockingly, Kaido took the full brunt of the assaults and stood unharmed. In only one swing of his club, he knocked Luffy out and crushed him completely. In this battle among Kaido, Luffy's assaults to the Yonko Kaido was nothing more than a simple type of exercise. He didn't felt any pain and deemed Luffy and his techniques as a mere pest.

Kaido dismantled Luffy with a single blow from his club with ease signifies that he was far stronger than any opponent Luffy have ever faced so far.