#5 – Former Admiral Aokiji (Kuzan)
Kuzan is a former Marine admiral. He was nominated by Sengoku for the position of fleet admiral but after losing the position to Sakazuki, he resigned from the Marines and affiliated himself with the Blackbeard Pirates.
Kuzan has the powers of the Hie Hie no Mi, a Logia Devil Fruit that allows him to control, create, and become ice. In battle, he uses his ice powers to disable and immobilize enemies, freezing their bodies solid just by touching them, and threatening to shatter their fragile forms. This fruit is so powerful that his usage of it during his ten day battle with Akainu permanently changed the weather on one side of Punk Hazard, turning that side into a frozen wasteland.
Kuzan was considered to be a massive asset to the Marines, and his departure left a negative impact to their military strength. This was confirmed by the Gorosei calling him an ‘enormous power’ while discussing his affiliation with the Blackbeard Pirates, to the point of being visibly distraught while doing so.
#4 – Current WG Commander-in-Chief & Former Fleet Admiral Kong
Kong is the World Government Commander-in-Chief. He was the Fleet Admiral of the Marines at the time of the Battle in Edd War twenty-seven years ago and at the time of Gol D. Roger’s execution twenty-four years ago.
Due to his muscles, his former rank in the Marines, and his numerous scars, he could be considered as one of the strongest marines ever, however he still has yet to reveal his powers in the series.
#3 – Current Inspector General Sengoku the Buddha
Sengoku the Buddha was the Fleet Admiral of the Marines pre-timeskip, succeeding Kong and preceding Akainu.
Alongside Garp and Tsuru, Sengoku is one of the most powerful Marines of his generation. Even without his Devil Fruit powers, Sengoku has enormous strength, enough to effortlessly hold down an enraged Garp with only one hand.
Sengoku ate the “Hito Hito no Mi, Model: Daibutsu”, a rarer-than-Logia Mythical Zoan-class Devil Fruit which allows him to turn into giant, living, Buddha-like golden statue, gaining an extreme boost in strength to match his size.
In this form Sengoku can launch golden shock waves to cause heavy and widespread damage to the enemies.
#2 – Current Fleet Admiral Akainu (Sakazuki)
Akainu is the current Fleet Admiral of the Marines.
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.
#1 – Current Vice Admiral Monkey D. Garp
Garp is one of the most powerful characters seen in the series so far. Alongside Roger, he fought and prevailed against the very powerful Rocks Pirates , which consisted of three future Yonkos, earning him the epithet of “Hero of the Marines”.
He is known for cornering and fighting Gol D. Roger many times. Roger also stated that he and Garp had almost killed each other on numerous occasions. As another true testament of sheer power, Garp defeated and nearly killed Don Chinjao in the past with a single punch, whose bounty was worth over 500,000,000 Berries in his prime and was said to be able to split a continent with a headbutt.
The extent of Garp’s power and fame is evident round the time of the Battle of Edd War, three years before the future Pirate King died. It was revealed that he was offered the promotion to the rank of Admiral more than once, but repeatedly refused the promotion.
Despite his advanced age, Garp still posseses tremendous strength.