Devil Fruits provide their users with special powers that enable them to take on strong opponents. Most Devil Fruit users just settle for the power that they receive and never try to push the limits. But there are certain One Piece characters who train with their Devil Fruits.
They learn about the strengths and weaknesses of their Devil Fruits. This gives them a better understanding and allows them to unlock powers that they normally wouldn't have access to. These One Piece characters show their creativity by using their Devil Fruits in the most ingenious ways possible.
7 Monkey D. Luffy
Monkey D. Luffy is the main protagonist of the series. He possesses the Hito Hito no Mi, Model: Nika. Initially, Luffy couldn't do anything special with his Devil Fruit, but he continued to train and improve. Luffy created different Gears that enabled him to beat opponents who were extremely strong.
Luffy's Gear Fifth is the pinnacle of his power, and in this form, he can extend the properties of rubber to other objects. In the fight with Kaido, the Supernova performed some of the most outlandish moves, which even perplexed the Yonko.
6 Charlotte Katakuri
Charlotte Katakuri is a Sweet Commander of the Big Mom Pirates. He was one of the main antagonists of the Whole Cake Island arc, where he clashed with Luffy in the Mirror World. Katakuri possesses the Mochi Mochi no Mi, a special Paramecia-type Devil Fruit.
It allows Katakuri to turn his body into mochi, and he could let attacks phase past him like a Logia-type user. Katakuri used the mochi to create massive fists, turn himself into a giant wheel, and imitate the techniques of other characters. Katakuri's creativity confused Luffy a lot, and the latter nearly ran out of options to defeat his opponent.
5 Doflamingo
Doflamingo is a former Shichibukai who is currently imprisoned inside Impel Down. He is a ruthless, malevolent individual who solely cares about achieving his goals. Doflamingo was exposed to the rough side of the world at a young age, and it resulted in him becoming a dangerous individual.
Doflamingo's Ito Ito no Mi is a Paramecia-type Devil Fruit that gives him the power to create strings. Normally, strings would not be classified as anything dangerous, but Doflamingo worked on his power and turned it into a fearsome weapon. He was able to use these strings to travel through the air, create a birdcage that was impossible to cut and create a clone of himself.
4 Enel
Enel was the tyrannical ruler of Skypiea. He came to the island after destroying his homeland. Enel was a Devil Fruit user, and on top of that, he was an exceptional Kenbunshoku Haki user. With the help of his powers, it didn't take long for Enel to take over Skypiea. The residents of Skypiea did not approve of Enel's methods, and many of them tried to oust him; however, the megalomaniac proved to be just too powerful.
He combined his Devil Fruit with his Kenbunshoku Haki to keep an eye on the activities of every single person on the island. He also planned to use his Devil Fruit power to power the Ark Maxim and travel to the Fairy Vearth. Enel was also able to resuscitate himself after nearly dying in a fight. Given that he could do so many things with his Devil Fruit, it is obvious that he is extremely creative.
3 Trafalgar Law
Trafalgar Law is the captain of the Heart Pirates and one of the most powerful characters in the story. Law's Ope Ope no Mi is quite possibly the most overpowered Devil Fruit in the entire series. Not only does it allow him to perform the most complex medical procedures, but it also enables him to fight strong opponents.
While Law could easily just spam ROOM multiple times, he decided to improve his abilities. Law can use his Devil Fruit in various ways. He can use his Devil Fruit to switch the hearts of different people, damage someone without cutting them, create a room where the voice doesn't go out, etc. Law has also awakened his Devil Fruit, which increases his power and grants him additional abilities.
2 Bartholomew Kuma
Bartholomew Kuma is a former Revolutionary-turned pirate. He was a member of the Shichibukai, and he was considered to be among its strongest members. At some point in his life, Kuma ate the Nikyu Nikyu no Mi. This caused Kuma's palms to develop paw-like structures.
Kuma used these paws to deflect or absorb the impact of the attacks of his enemies. He could also use the Devil Fruit to send people flying from one place to another. Kuma is also able to extract physical damage from someone's body. All these techniques prove that Kuma was extremely creative at using his Devil Fruit.
1 Kaku
Kaku is a member of CP0, and he was introduced in the Water 7 arc as a Galley-La shipwright. It wasn't until later that he was revealed to be a member of CP9. During his first confrontation with the Straw Hats, Kaku had not eaten a Devil Fruit.
He received his Devil Fruit in Enies Lobby. Kaku's Ushi Ushi no Mi, Model: Giraffe enabled him to turn into a giraffe, which greatly affected his fighting style. However, Kaku managed to come up with different kinds of attacks that would incorporate his Devil Fruit ability. He came up with all the different kinds of attacks in a very short time, which reflects his ingenuity.