Weaknesses. Despite these advantages Luffy is not immortal. Though immune to lightning, he can be damaged by other elements such as fire or ice, attacks involving cutting or stabbing and Haki-infused attacks.
The Devil Fruits as well as specific other powers of One Piece can frequently fall into Logical Weakness. Luffy's rubber body, which makes him more or less immune to blunt force, renders him no less vulnerable to blades than he ever was. For Luffy, heat also apparently makes him extra squishy.
What is Luffy's weakness? All Devil Fruit Users' weakness is water, the same goes for Luffy.
Luffy is a rubber man is because as a child he ate the Gomu Gomu no Mi (Gum-Gum Fruit). However, all users of such fruits share the same weak point: seawater. They cannot swim and lose all their strength when they come into contact with the ocean. This is one of the great ironies of the series.
In addition, Luffy still has his standard weakness to cutting attacks.
Luffy is confirmed to have overcome his weakness of shrinking when deactivating this Gear, after inflating both his arms and using "Gomu Gomu no Elephant Gatling" on Noah for a prolonged period of time and not turning into his chibi form.
6 Gear Fourth's Debilitating Weaknesses
If the form fails to get the job done, then Luffy is rendered too exhausted to be able to defend himself, especially if he is unable to get his hands on some food to replenish his reserves.
Nami was one of the first characters to join the Straw Hat Pirates, and remains an extremely important character to the story. When it comes to strength, she's the weakest member of the crew, which is why she often relies on clever tricks and strategies in battle.
Luffy's greatest power-up to date is, undoubtedly, Conqueror's Haki coating. During his fight against Kaido, Luffy observed Kaido coating his weapon in Conqueror's Haki. After this realization hit him, he was able to use a crude version of this technique himself and could coat his fists in Conqueror's Haki.
Naruto Possesses Massive Firepower
In his base form, Naruto is immensely strong. However, when he combines his Six Paths Sage Mode and his Kurama Mode, he is stronger than anything Luffy will ever face. Even if Luffy were to get 10 more Gears, he still wouldn't be strong enough to stand up to Naruto in this mode.
The fight is, undoubtedly, the most difficult one that Luffy has fought so far. Kaido managed to defeat Luffy three times. For the first time, Luffy faced defeat against him Kuri and was thrown in prison. There, he learned Internal Destruction Ryuo and took Kaido on during the Onigashima Raid.
Roger. This sets up Shanks and the Red Hair Pirates as straight-up rivals of the Straw Hats, whose goal is to make Luffy the Pirate King by finding the One Piece. Compared to Luffy's other big rival, Blackbeard, Shanks has a huge advantage. As a kid, he was a member of Gol D.
However, physical blows without Haki don't work on him due to his rubber body, and the only slashing-style ninjutsu Sakura is shown to know is a scalpel-like blade. With that being her only weapon to hurt Luffy with, it's likely she will lose this fight in embarrassing fashion.
It depends on how quick the fight will last. Luffy's Gears are costly and can't be maintained for long stretches of time and neither can Baryon Mode for Naruto. Due to the number of drawbacks the Baryon Mode brings, Luffy will probably clinch victory in Naruto vs. Luffy if they break those modes out.
Gear 5 is Luffy's pinnacle power, and he can do anything he wants in this form. Furthermore, it is mentioned that his powers are only limited by his imagination. With this gear unlocked, Luffy is said to resemble the “Warrior of Liberation” — Sun God Nika, who is said to bring smiles, joy, and freedom to the people.
Imu is the sovereign of the World Government and arguably the strongest character in One Piece. Imu seems to have access to some kind of ability/weapon that allowed him to destroy the Kingdom of Lulusia in an instant.
Nami. Nami may be the weakest crew member, when it comes to strength, but she is far from useless. Her navigation, weather prediction, and cat burglary skills are unmatched. Nami knows she is nowhere near as strong as the other crew members but that doesn't keep her out of a fight.
Gum-Gum UFO allows Luffy to miraculously hover in the air, essentially giving him the power of flight, a skill coveted by many. Gear Four also gives Luffy the ability to fly, but Gum-Gum UFO doesn't come with the same haki-depleting consequences.
As for fire, rubber can be burned all the same, so, yes, he's vulnerable to fire and heat. Yes. He got hurt by Wiper's burn bazooka. Also, when Enel can't hurt him with electricity, he used heat to hurt Luffy.