Luffy is the main protagonist of the One Piece universe and the captain of the Straw Hat crew. Over the years, he has embraced the necessity of becoming stronger in order to protect his friends and fulfill his aspirations. He has displayed incredible adaptability, sometimes even learning new skills in a matter of days.
The young pirate's power reflects in the opponents he has fought, ranging from Buggy to Kaido. By identifying the ways that he's become stronger and rose to the challenge, we can better appreciate his hard work and the things it has enabled him to do.
10 Luffy Mastered His Gum-Gum Fruit
Although the Gum-Gum fruit had boundless potential, it wasn't easy to learn. At first, Luffy struggled with throwing something as simple as a straight punch without his arm going limp.
He perfected his skills with Ace and expanded upon them ever since setting sail. Through countless battles, he has learned useful techniques like the Gum-Gum balloon and battleax. The former was capable of deflecting entire naval barrages, and the latter destroyed Arlong Park in a single hit.
9 Luffy Learned Second Gear, A Technique That Increased His Speed & Strength
When confronted by the threat of CP9, Luffy's options were limited. They were incredibly fast, and even if he connected his punches, their "Iron Body" technique limited what damage he could do.
In order to save Robin, he developed the Second Gear technique. By accelerating the flow of blood pumping through his body, he increased both strength and speed considerably. Lucci noted that the technique was not without drawbacks - it took a serious toll on his stamina and even his health. However, Luffy has honed it nicely under Rayleigh's watchful eye.
8 Luffy Gained A Tolerance To Poisons By Fighting Magellan
Luffy's fight against Warden Magellan was a complete disaster. Without armament Haki, he had no way to combat the man's logia-type devil fruit. Worse yet, any efforts to hit him would have an immediate and profoundly negative effect.
However, it wasn't a complete loss. Luffy survived the encounter with Ivankov's help and even developed a high tolerance for poison. This came in handy during Punk Hazard, where he resisted Caesar Clown's noxious gases during their fight. However, he does not have complete immunity, as proven when eating a toxic fish on Whole Cake Island.
7 The Size Of Luffy's Crew Has Expanded Considerably
When Luffy first set sail, he did so alone. He quickly began recruiting in the East Blue, with his crew rapidly expanding in size until Chopper's introduction.
Nico Robin eventually joined following the events of Alabasta, helping to translate Skypiea's poneglyph. Franky became a member of their crew once Spandam was defeated, and Brook signed up shortly after recovering his shadow from Ryuma. Jinbe joined the crew last after "satisfying" his obligation to Big Mom. All of Luffy's friends have been invaluable in his quest to become the King of the Pirates.
6 Luffy Learned Third Gear To Defeat Rob Lucci
Also known as "Bone Balloon," Luffy first came up with Third Gear in order to beat Rob Lucci. It had such tremendous striking power that it created a hole in the Tower of Justice and sent the villain flying into a marine ship all with a single hit.
However, it initially had a critical drawback. After using Third Gear, Luffy was briefly reduced to the size of a child. As a result, the captain took big risks when using Third Gear on opponents he failed to immediately defeat.
5 Luffy Gained Observation Haki
Observation Haki allows a person to predict their opponent's next moves and react accordingly. Luffy first encountered it during his stay on Amazon Lily, where Boa Hancock's retainers used it to fight efficiently against him. At the time, he failed to realize how his opponents kept anticipating his attacks.
Eventually, Luffy discovered the way to learn such awe-inspiring power firsthand. During the events of Whole Cake Island, he refined it further, developing an advanced form of observation Haki that proved essential during future endeavors on Wano.
4 Luffy's Armament Haki Made Him Competitive Against Logia Users
At first, Luffy struggled against logia users like Crocodile and Smoker. Their devil fruits made them too elusive for him to hit, and as a result, most encounters were brutally one-sided.
Over the time skip, Luffy turned the tables by learning armament Haki. Not only did it allow him to strike directly at elemental opponents, but it also enhanced the defensive and offensive potential of ordinary attacks. His headbutts alone became so powerful that they could launch Hody Jones several dozen yards into solid rock.
3 Luffy Used Conqueror's Haki To Incapacitate Dozens Of Opponents
Conqueror's Haki is extremely rare and for good reason. It is powerful enough to incapacitate hundreds of opponents at once, and only the strongest wills can hope to resist it.
Luffy first discovered this power on Amazon Lily when pacifying many of Boa Hancock's subjects. He also used it at Marineford in a desperate attempt to save Ace. In each instance, those who remained standing were in awe of the Straw Hat captain's rare and unparalleled skill. Unfortunately, it made him an even greater target for the World Government since he may one day grow too powerful to subdue.
2 Luffy Refined All Of His Abilities Under Rayleigh
During the two-year time skip, Luffy benefitted tremendously under Rayleigh's training. In addition to mastering the aforementioned forms of Haki, he also reduced the drawback on the techniques of his Gum-Gum devil fruit.
For example, Second Gear no longer had a high stamina or health cost, and he could even use it without making its iconic pose. Additionally, Third Gear no longer made him vulnerable after a single usage. The latter proved instrumental in his battle with Doflamingo, as the Warlord would have capitalized on any weakness Luffy showed him.
1 Luffy Learned Fourth Gear In Order To Defeat Doflamingo
Luffy first used the Fourth Gear technique in order to defeat Doflamingo during the battle for Dressrosa. Despite its silly appearance, it increased his strength and speed to such astronomical extents that it even enabled flight.
However, it also had the longest recovery time of any ability Luffy had used so far. As a consequence, he needed ten whole minutes in order to regain his strength before dealing the punch that would defeat Doflamingo for good. In the end, Fourth Gear presents a high risk for an even greater reward.