16-BLACKBEARD
Blackbeard is the admiral of the Blackbeard Pirates and the newest member of the Yonko. He has an immense amount of superhuman endurance and tremendous physical strength even for his comparable size.
Blackbeard has become the first and, so far, only user to wield the powers of two Devil Fruits at the same time. With the power of darkness (Yami Yami no Mi), which “reduces anything to nothingness”, and the power of quakes (Gura Gura no Mi), which “brings destruction to everything”, Blackbeard claims himself to be truly invincible and the strongest pirate in the world.
The most prominent feats of Teach’s power was defeating three commanders of the Whitebeard Pirates: Portgas D. Ace, Thatch, and later during the Payback War, Marco, the new Captain of the Whitebeard Pirates.
17-BIG MOM
Big Mom, is the captain of the Big Mom Pirates and the only female member of the Yonko.
Big Mom has immense superhuman physical strength and tremendous superhuman durability due to her extremely tough skin. Mother Carmel believed she had the potential to become an Admiral or Fleet Admiral of the Marines.
Big Mom is one of the very small number of people in the world who can use all three types of Haki.
Big Mom has acquired the powers of the Soru Soru no Mi a powerful Paramecia-type Devil Fruit that allows her to manifest the soul of whomever she touches into an ethereal substance. She can put harvested souls into non-living things in order to give them life or into animals in order to give them human abilities. Those creatures are named Homies. She can also use fragments of her own soul to create Special Homies that are far more powerful than ones created with other people’s souls: Zeus, a thundercloud she summons with her left hand; Prometheus, a sun she summons with her right hand; and Napoleon, a bicorne she wears on her head.
18-KAIDO
Kaido of the Beasts is renowned as the “Strongest Creature in the World”. He attempted to take Whitebeard’s life, something few would dare, and subsequently clashed with Shanks. When Gekko Moriah was in his prime, Kaido fought him and emerged victorious, having killed his entire crew. In Wano, Kaido defeated Luffy with just one hit!
Kaido has eaten a Mythical Zoan-type Devil Fruit that allows him to transform into a massive, blue-scaled Eastern dragon.
Kaido has tremendous physical strength, but the greatest sign of his strength is his apparent inability to die due to his tremendous toughness and durability. He has been caught and tortured 18 times, and people as powerful as the Marines and other Yonko have attempted to execute him 40 times only to fail as Kaido survived every single attempt because every single execution weapon broke when being used on him. Most notably, Kaido has jumped from 10,000 meters from the sky onto the ground, creating a massive shockwave strong enough to sink a large ship nearby, and emerged only with a headache; it has even become a hobby for him to attempt suicide, only for it to fail.
Notably, Kaido has a bounty of 4,611,100,000 Berries, which is the highest of any pirate currently alive, surpassed only by the bounties of the late Whitebeard and Gold Roger.
19-SHANKS
“Red Haired” Shanks is Luffy’s role model and the man that our main protagonist wants to surpass one day. It makes sense in the series that Shanks is powerful because he is that character that the main protagonist wants to fight last on his journey. Shanks’ full fighting potential hasn’t been explored yet but there is a lot of hints that indicates Shanks is an extremely powerful individual. For starters, he was able to scare off a massive Sea King just by staring at it (until we figured out he used Conquerors Haki: the strongest form of Haki). He also clashed evenly with Whitebeard, a fellow Emperor and even fought another, Kaido, and arrived at Marineford without a scratch on him. Additionally, he managed to ward off Ankinu where the savage admiral seemed a bit shocked at his presence and stopped going after Luffy after he came. Most of all, Blackbeard, who had the powers of the destructive Gura Gura no Mi Fruit and the evil Yami Yami no Mi Fruit chose not to fight Shanks saying “he is not strong enough to fight him yet”.
Shanks has mastered to full extent all 3 types of Haki. He’s the only character so far with an Haoshoku Haki that actually damaged physical things.
All that makes Shanks a force to be reckoned with and definitely one of the strongest guys in the series.
20-AKAINU
Akainu has shown to possess tremendous strength and an immense amount of superhuman durability.
He possesses the Magu Magu no Mi, a Logia-class Devil Fruit which grants him the ability to transform his body into magma and manipulate it at will, as well as produce near-limitless amounts of it. His ability is naturally of a higher order than Ace’s pyrokinetic abilities, as the higher heat and smothering abilities of his magma allowed him to successfully harm Ace despite Ace’s Logia-defense, and ultimately kill Ace due to this superiority. According to Oda, Akainu’s devil fruit boasts the highest offensive power amongst all the Devil Fruits.
During the decisive ten day battle on Punk Hazard for the position of fleet admiral, Akainu showed the furious power of his Devil Fruit as he changed the weather of one side of Punk Hazard and left it in a blaze.
Eiichiro Oda stated that if Akainu were to become the protagonist, he is so strong that he could end the One Piece series within a year.