The a piece The story features an incredible power system that stems from the mystical power of Devil Fruits. Within this power system of Devil Fruits, the creator of the story, Ichiro Oda, established three types of fruits: Joan, Paramecia, and Logia. The most common and versatile type is Paramecia, which does not follow any special rules. While most a piece While transformations are usually generated from Zoan Fruits, there are some impressive Paramecia Fruits that offer extreme power changes and allow the user to take on stronger enemies.

One Piece: 10 Devil Fruits that can kill in one-shot
Devil Fruits offer various offensive abilities, and some are so powerful that they can kill in one shot.
8
Shadow Asgard of Geko Moria
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User: Gekko Moriah
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Devil Fruit: Kage Kage no Me
Geiko Moriya is a member of the Shichibukai that Luffy and the Straw Hat Pirates come face to face with during the Thriller Bark arc. Back then, Moria was definitely a formidable opponent. He ate Kage Kage no Mi, giving him control over Shadow. With his Devil Fruit, Moria unlocks a powerful Paramasia transformation called Shadow's Asgard. By collecting shadows and then absorbing them into himself, he grows in strength, size and power. His power level is directly related to the amount of shadow he takes and the base strength of the shadow. This form can be a bit difficult to control, which was his undoing, but in terms of power, it is immaculate.
7
Pika's Stone Form
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User: Pica
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Devil Fruit: Ishi Ishi no Me
Dressrosa Arch Off a piece Luffy and some of the Straw Hat Pirates watch Dressrosa play with the Donquixote family in hopes of freeing them. As Doflamingo took center stage, another of his subordinates was highlighted by Pika.
Pika uses Ishi Ishi no Mi. This Paramecia devil fruit that allows him to fuse with stone and manipulate it. With this power, Pica was able to fuse and capture a large portion of the Plateau of Dressrosa. This allowed him to attain a giant form made of stone. This is one of the biggest changes seen a piece. His power was definitely overwhelming at first, and Zoro had to figure out Pika's own body in particular.
6
Sanjuan Wolf's body extension
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User: Sanjuan Wolf
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Devil Fruit: Deca Deca No Me
Sanjuan Wolf is one of the strongest pirate crews around, the Blackbeard Pirates. During the timeskip, the Blackbeard Pirates only grew in strength as they collected superpowered Devil Fruits to feed their core members. At the same time, during the timeskip, an incredible Paramasia Devil Fruit known as Deca Deca No Me appeared. This devil fruit allows one to change their shape and grow exponentially.
On the surface, this may seem a bit weak. However, for a giant like Sanjuan Wolf, being able to grow ten times in size meant he could even achieve the size of an island. This is an incredibly destructive power, and he can take on some of the strongest characters in the world in one piece using his sheer size alone. This Devil Fruit transformation is not to be underestimated and has cemented itself as the most OP of the Paramecia type.
5
Demonio Fleur
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User: Nico Robin
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Devil Fruit: Hana Hana no Mi
Nico Robin is the archeologist of the Straw Hat Pirates. In her possession, she has Hana Hana no Mi, or Flower Flower Devil Fall. This fruit allows him to sprout his body and individual parts almost anywhere, and even combine them to produce larger organs.
Robin's Devil Fruit was taken to the next level during the raid on Onigashima, where she battled the strongest Tobiroppo, Black Maria. In this battle, Robin unlocked her strongest transformation, Demonio Fleur. In this form, Robin's skin turns red, and her size increases greatly. She also sprouts demonic wings and horns. In this form his strength increases greatly, and he was even able to brutally break Black Maria's back.

One Piece officially welcomes Monkey D. Luffy's new Haki Power Up
Eiichiro Oda has officially upgraded Luffy's Haki during the battle against Nerona Emu in chapter 1186 of the manga.
4
poison demon
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User: Magellan
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Devil Fruit: Doku Doku no Mi
in a pieceNot many opponents have caused Luffy as much trouble as Magellan. Magellan is the former Warden of Impel Down, and he acted as a major obstacle between Luffy and Ace during the Impel Down arc. He has a Paramasia type Devil Fruit known as Doku Doku no Mi. This fruit allows him to produce deadly poisons that can kill almost anyone it touches.
With this power, Magellan can tap into one of the most devastating Paramasia transformations known as the Venom Demon. Magellan produces a large amount of deadly poison that takes the form of a monster. This transformation gives him a massive appearance and makes him poison anything he touches or around him.
3
big daddy
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User: Capone Bege
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Devil's Fruit: Shiro Shiro no Mi
One of the forgotten but still influential members of the Worst Generation, Capon Baggie played a major role during Whole Cake Island, where he decided to aid the Straw Hat Pirates in their attempt to assassinate Yonko Big Mom. This assassination attempt quickly turned sour when Big Mom was able to easily knock back their attack with her Conqueror's Haki.
To protect himself from the Big Mother pirates, Bege unleashed the final form of his Shiro Shiro no Mi – Big Father. Big Father allows Bege to turn it into a fortress. The fort was definitely strong and could withstand many attacks, but against someone like Big Mom and her crew, it wasn't enough. It still remains one of the most impressive Paramecia-based transformations in the series, and a strong user can make it even stronger.
2
Gear 5
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User: Jewel Bonny
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Devil Fruit: Toshi Toshi no Me
Gear 5 is technically Monkey D. Luffy's ultimate ability which he uses with his legendary Zoan Devil Fruit, The Hito Hito no Mi, Model: Nika. However, this transformation has also been used in Egghead through the Paramasia devil fruit.
Jewel Bonnie demonstrates her true power with her Toshi Toshi no Mi. With this fruit, he is able to distort the future. After seeing Luffy use Gear 5, she sabotages her future self to become Nica and tap into Gear 5. While Bonnie's Gear 5 isn't as strong as Luffy's and doesn't last as long, it was still strong enough to fight against the Five Elders, an impressive feat, especially for a 12-year-old. This makes Gear 5 one of the strongest Paramecia conversions out there.
1
A great mother's spirit change
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User: Big Mom
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Devil Fruit: Soru Soru no Mi
When it comes to the strongest paramasia transformations out there, the strongest is undoubtedly Big Mom. Grandmother possesses Soru Soru no Mi, which allows her to extract and control spirits.
In the Wano arc, Big Mom took on two strong members of the Worst Generation – Trafalgar Law and Eustace Kidd. After the two awakened their Devil Fruits, Big Mom had to tap into her ultimate ability, which allows her to sacrifice a portion of her lifespan to gain a massive transformational power-up. In this transformation, the Great Mother greatly increases in size, and her power multiplies. With this form, Big Mom was technically never defeated. Instead, Law and Kid had to knock him off Onigashima. He also had explosives worth an island's stock that were accidentally thrown on him. This form remains, by far, the strongest Paramecia transformation out there.