Monkey D. Luffy is the main character of One Piece, and he ate the Human-Human Fruit, Model: Nika - a Mythical Zoan Devil Fruit that gives his body the properties of rubber. Luffy's Gear 5 transformation is the byproduct of Devil Fruit awakening, and it allows him to fight with complete freedom because everything he touches becomes rubber too. It also utilizes advanced Conqueror's Haki. Gear 5 is Luffy's strongest form, but it can be defeated by several Quirks from My Hero Academia.
Some of the Quirks that can beat Gear 5 Luffy belong to Pro Heroes who typically use their powers to help others. My Hero Academia also has Villains who use their Quirks to commit crimes, and several of those Quriks can beat Gear 5 Luffy too. Some of these Quirks can beat Gear 5 Luffy in special ways, while others can beat him through direct physical contact.
10 Compress Can Turn Gear 5 Luffy Into A Marble
First Used In Episode 44: "Roaring Upheaval"
Compress gives someone the ability to shrink anything, but they must physically touch the object with their hands. When the object shrinks, it becomes a small marble, and the user is the only person who can reverse the transformation. Compress can also shrink living beings - which means that the user can end any fight instantly.
Luffy may be able to treat other surfaces and objects like rubber while using his Gear 5 transformation, but he would not be able to move if he is turned into a marble. Luffy possesses immense Conqueror's Haki, but even that cannot nullify Compress' effects. It should also be noted that Compress can be used on specific body parts. If Luffy is not careful, Compress can permanently sever his limbs.
9 Black Hole Has The Power To Destroy Any Awakened Zoan User
First Used In Episode 10: "Encounter with the Unknown"
Black Hole is one of the most dangerous Quirks in existence, but civilians do not need to worry because it is currently in the hands of Thirteen - a Pro Hero who specializes in search and rescue. The user can replicate the suction effect of a black hole with their hands. The pull is so strong that even light cannot escape from it. Any physical matter that gets sucked into the user's hands gets disintegrated. The one downside is that the user can only aim Black Hole in a single direction.
That being said, it would be very difficult for Luffy to escape Black Hole's pull once he is caught in it. Luffy can try coating his body in Haki, but even Haki cannot survive disintegration. His best bet would be to wrap his body around something, but even then, Black Hole can remain active until Gear 5 deactivates. At that point, Luffy would be too weak to do anything.
8 Water Control Can Take Away Luffy's Devil Fruit Powers
First Used In Episode 10: "Encounter with the Unknown"
Water Control is one of the Quirks that Class 1-A students dealt with when Villains attacked the Unforeseen Simulation Joint Facility. As its name suggests, it gives someone the ability to manipulate water. The user cannot create water though, which means that Water Control is only effective if they have access to a body of water. This Quirk can be highly effective against Gear 5 if Luffy is fighting on a ship or coastline.
If that is not the case, the user can find a way to bring seawater onto the battlefield. Seawater nullifies Devil Fruit Powers, and it drains Devil Fruit users of their energy. Someone with Water Control can blast Luffy with seawater to instantly deactivate Gear 5. They could also trap him in a ball of seawater until he drowns.
7 Somnambulist Can Put Gear 5 Luffy To Sleep
First Used In Episode 23: "Shoto Todoroki: Origin"
Somnambulist is one of the many Quirks that were introduced in My Hero Academia's second season. It is not an offense driven Quirk, but it can take Luffy and the other current Yonko down. Somnambulist allows its user to produce a sleep-inducing aroma from their skin. Luffy's body has developed a resistance to certain poisons, but this aroma does not qualify as a poison.
For some reason, Somnambulist is highly effective against men, so Luffy would be put to sleep even if he is using Gear 5. Granted, he can avoid it by holding his nose, but in order for that to work, he would need to know about Somnambulist's effects ahead of time. If Luffy is put to sleep, the user can drag him into the sea or finish him off with some type of bladed weapon.
6 If Luffy Gets Cut, Bloodcurdle Can Paralyze His Geart 5 Transformation
First Used In Episode 28 : "Midoriya and Shigaraki"
Bloodcurdle is the terrifying Quirk associated with Hero Killer Stain, and it can theoretically take Luffy down because his Gear 5 transformation can still be harmed by blades and slashing attacks. Bloodcurdle can instantly paralyze someone, but the paralysis will only occur if the user tastes some of their target's blood. The length of the paralysis depends on the person's blood type.
Luffy's blood type is F, which means that he could be paralyzed for up to five minutes. If that is the case, Luffy's Gear 5 transformation may run out, and he will be left in a heavily weakened state. As long as the user has access to Luffy's blood, Bloodcurdle can keep paralyzing Luffy until Gear 5 deactivates. If this happens, Luffy would be too weak to use defensive Haki, and the Bloodcurdle user would be able to finish him off with a sword.
5 Reflect Would Cause Luffy To Be Hit By His Own Attacks
First Used In My Hero Academia: World Heroes' Mission
Reflect is a Quirk that was introduced in My Hero Academia: World Heroes' Mission. It may not be part of the official canon, but it is still capable of defeating Gear 5 Luffy. Reflect is constantly active, and it gives the user the ability to absorb any type of energy before sending it back towards their opponent. As of now, Bajrang Gun is Gear 5 Luffy's strongest attack.
If he were to use it on a Reflect user, he would get hit by all of the attack's Haki-infused power. Bajrang Gun defeated Kaido, so it would do a lot of damage to Luffy. As long as the Reflect user has enough stamina, they would be able to reflect an entire Gear 5 punching barrage back at Luffy. Reflect would basically cause Luffy to lose to his own Gear 5-level strength.
4 Brainwashing Can Force Luffy Into Seawater
First Used In Episode 20: "Victory or Defeat"
Brainwashing is the type of Quirk that would normally be associated with a Villain, but it currently belongs to an aspiring Pro Hero. Like its name suggests, Brainwashing forces others to obey the commands of the user. It can be used on multiple people at once, and it will only trigger if the target verbally responds to the user. That being said, the effect will only activate if the user actually wants to brainwash someone.
Luffy is not the brightest person, and he tends to reply to his enemies, so Brainwashing will definitely take hold of him. The user can force Luffy to walk into the sea - which would nullify his Gear 5 transformation and ultimately drown him. Luffy could also be forced to put on Seastone handcuffs, which would negate his Devil Fruit power as well.
3 Rewind Can Revert Luffy Back To A Point When He Never Ate His Devil Fruit
First Used In Episode 76: "Infinite 100%"
Rewind can be used to heal serious injuries, but it is also one of the most dangerous Quirks in the world. Its power was synthesized into special bullets that could turn Pro Heroes into ordinary humans. At its core, Rewind can revert another living person to a previous state. If Gear 5 Luffy is close enough, the user can revert him back to a time before he awakened his Devil Fruit.
This means that Luffy would need to re-awaken Gear 5 in order to use it again, and that may be difficult since he only awakened it when he was on the verge of death. If that was not bad enough, the Rewind user can literally wipe Luffy from existence by reverting him to a time when he was not even born.
2 Overhaul Can Blow Gear 5 Luffy's Body To Pieces
First Used In Episode 62: "A Season for Encounters"
Overhaul is the type of Quirk that can kill any character in One Piece because it can bypass Devil Fruits and Haki. If it was not for Eri and her Quirk, Overhaul would have easily killed Izuku midoriya. The user has the power to dissassemble anything with their hands, and they can reassemble things however they want. Overhaul essentially gives the user complete control over matter.
Luffy is still a melee fighter when he uses Gear 5, which means that he cannot avoid making contact with an Overhaul user. If the user manages to touch Luffy's Haki-infused arm during an attack, that arm will instantly blow apart. There will practically be nothing left of Luffy if the user touches any part of his upper body.
1 Decay Can Disintegrate Luffy's Gear 5 Body
First Used In Episode 11: "Game Over"
Decay gives its user the power to disintegrate anything. Under normal circumstances, the user would need to touch an object or person with all five of their fingers in order for Decay to activate. If the Quirk goes through an awakening, the user can trigger it without needing all five digits. More importantly, the disintegration can spread over a wide area and kill dozens of targets at once.
The user can allow themselves to get hit by Luffy in order to touch him. If Decay targets an arm or leg, Luffy can stop it by cutting off the limb, but he will be severely weakened as a result. If the user touches part of Luffy's head or upper body, it will be game over because even Gear 5's Haki-infused durability cannot withstand disintegration.
