- Some Marines leave the organization to pursue their own goals or because their motives don't align with those of the World Government.
- Former Marines like Morgan, Diez Barrels, Jaguar D. Saul, and Sentomaru have all severed their ties with the Marines for various reasons.
- Kuzan, also known as Aokiji, left the Marines and joined the Blackbeard pirates, becoming one of their strongest members. Monkey D. Dragon formed the Revolutionary Army to overthrow oppressive rulers and is now known as the worst criminal in the world.
The Marines are one of the biggest and strongest organizations in One Piece. They work for the World Government and ensure that no harm comes to its leaders. The Marines are generally considered the upholders of justice, as it is their job to get rid of pirates and other criminals.
However, not every Marine's motives align with those of the organization. This often leads to many Marines resigning and leaving to pursue their own goals. In some other cases, they are kicked out and labeled outlaws.
Kicked Out Of The Organization
Morgan was the main villain in Shells Town. He was a self-conceited man who wanted to be the center of attention all the time. He even forced his underlings to make a statue in his honor, and he would bully them if they refused to listen to his orders.
Morgan had an axe instead of a normal hand, which made him look scary. He didn't hesitate to use it against fellow Marines if they annoyed him. Morgan was ultimately defeated by Luffy, and his status was revoked. Thus, Morgan's affiliation with the Marines came to an end.
5 Diez Barrels
Marine Turned Pirate
Diez Barrels was affiliated with the Marines a very long time ago but left the organization to become a pirate. He never stated the reason behind his decision, but it is possible that he wanted to be something more than a mere soldier. At some point, barrels found the Ope Ope no Mi, a Paramecia-type Devil Fruit. He knew that there was a huge market for buying and selling devil fruits, so he decided to test his luck.
He ended up making a deal with the Marines, who wanted the Devil Fruit. Barrels demanded a hefty sum of five billion berries, which the organization agreed to pay. Unfortunately, before the deal could go down, Corazon stole the Devil Fruit and gave it to Law. When Doflamingo arrived at the location, he murdered Barrels in cold blood.
4 Jaguar D. Saul
Left The Marines Willingly
Jaguar D. Saul was a Vice Admiral who served the Marines loyally for a long time. As a giant, he had absurd physical strength, making him a valuable asset to the organization. But he left the Marines after learning about their intentions to wreak havoc in Ohara. Saul became a deserter and eventually ended up in Ohara, where he became friends with Nico Robin.
During the Buster Call, Saul protected Robin from harm and even stood up to Aokiji. The latter froze him using his Hie Hie no Mi. After the Ohara massacre, Saul was presumed dead. However, Vegapunk confirmed that the giant had managed to survive and was currently living in Elbaf.
Prioritized The Safety Of Vegapunk
Sentomaru was introduced in the Sabaody Archipelago arc as one of the supporting antagonists. He was in charge of the Pacifista that were deployed on the island. He continued to make appearances in other arcs where he also acted as a villain. He was in charge of the Marines' Science Unit because he was closest to Dr. Vegapunk. Sentomaru possesses two types of Haki, and he can use both of them to the highest degree.
In the Egghead arc, it was revealed that he was fiercely loyal to Dr. Vegapunk and did not care about his position as long as the scientist was safe. He even fought against Rob Lucci and Kizaru to ensure that no harm came to the scientist. Due to his actions, it is safe to say that he is no longer affiliated with the Marines.
Currently Part Of A Yonko's Crew
Kuzan used to be a Marine Admiral who followed "Lazy Justice." He was not overtly aggressive and would keep his cool in the most tense situations. Kuzan was one of the main reasons why the Marines were successful in executing Ace and winning the Paramount War. He used his Devil Fruit to freeze the tidal waves created by Whitebeard, and had he not done so, the entire island would have suffered immense damage.
Kuzan left the Marines after failing to defeat Akainu on Punk Hazard. The two Admirals battled for several days in order to find the successor to Sengoku's Fleet Admiral position. Following his departure, Kuzan joined the Blackbeard pirates and became one of the ten Titanic captains. Currently, he is one of the strongest members of the crew, as evidenced by his victory over his former mentor, Monkey D. Garp.
1 Monkey D. Dragon
Worst Criminal In The World
Monkey D. Dragon is indubitably the most well-known former Marine in One Piece. For years, fans speculated that he was a soldier for the organization, but it wasn't confirmed until the Egghead arc. While viewers are aware that he was working for the organization, his position within the Marines remains unknown.
Dragon left the Marines after seeing how they danced to the tune of the World Government. They didn't have any authority, and all they could do was follow orders from the higher-ups. Dragon started the Revolutionary Army in hopes of overthrowing oppressive rulers throughout the world. In a short time, he was joined by many people. Currently, he is known as the worst criminal in the world, and it is plausible to assume that he has one of the highest bounties in One Piece.