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One Piece: The Diary of Koby-Meppo Arc | Summary, Recap & Review

Explore Koby and Helmeppo's Marine journey in the Diary of Koby-Meppo arc. Danger, growth, and secrets await in One Piece's Arabasta Saga.



The Diary of Koby-Meppo Arc follows Koby and Helmeppo's quest to become Marines, showcasing their growth and newfound sense of justice. The arc offers character development, loyalty, and redemption for the two.


  • Interesting character development of Koby and Helmeppo.
  • Fun themes of friendship and determination.


  • Slow-paced initial focus on chores.
  • A bit predictable in terms of character transformation.
One Piece Diary of Koby-Meppo Arc One Piece Diary of Koby-Meppo Arc

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The world of One Piece is one filled with pirates and adventures, there’s danger in every corner and all kinds of powerful enemies all around. Even so, one of the constant enemies in the series are the Marines and the law enforcement personnel. So we tend to forget that even the lowest level ones are people with entire backstories.

This arc provides a rare glimpse into the Marines' headquarters, where two young cadets defy challenges to train and become honorable and formidable Marines, dedicated to serving others. Of course, these aren’t just any cadets, as we’re following Koby, Luffy’s friend that dreamed of becoming a strong marine and capturing criminals, and Helmeppo, his unlikely friend.

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Join us on a thrilling journey as we dive into the Diary of Koby-Meppo, an introductory arc in the Arabasta Saga of the renowned manga and anime series, One Piece. This exciting arc follows the adventures of Koby and Helmeppo as they undergo rigorous training to become Marines. From menial janitorial tasks to unexpected encounters with dangerous criminals, this arc is filled with twists and turns that will keep you on the edge of your seat.

One Piece The Diary of Koby-Meppo Arc Summary & Recap

A Rocky Start: Chores and Challenges

One Piece Koby calls Helmeppo his friend

The Diary of Koby-Meppo begins with Koby and Helmeppo, eager to prove themselves as Marines, but finding themselves burdened with an overwhelming amount of janitorial work. While Koby takes the tasks in stride, his companion Helmeppo struggles with his anger and frustration. He misses his old life of privilege and power,

They both see Luffy in a different light, but that difference of opinion will be something common among these two, as they are pretty much opposites. This incident with the doll highlights the contrasting attitudes of the two characters and sets the stage for their personal growth throughout the arc. The friction between these two would serve as an excellent catalyst and motivation for each other.

A Glimpse of Hope: Training on the Ship

One Piece Axe Hand Morgan Breaks free and takes Helmeppo as a hostage

Amidst their mundane chores, Koby and Helmeppo are unexpectedly assigned to a ship tasked with transferring the notorious prisoner, Morgan. This revelation shocks them, particularly Helmeppo, who fears for his father's life.

However, a surprising turn of events occurs when they spot Vice Admiral Garp's ship approaching. As Garp prepares to take custody of Morgan, a tense moment ensues when Morgan unexpectedly attacks and kidnaps Helmeppo. In a courageous act, Koby steps up to protect his friend.

This immediately gets the attention of Vice Admiral Garp, who already had an eye out for these two anyway.

A Defining Moment: Koby's Stand

One Piece Koby stands in the way of other marines about to shoot Morgan

Faced with the imminent danger of Morgan's escape, Koby finds himself at a crossroads. The Marines prepare to fire on the fleeing vessel, but Koby, driven by his loyalty and friendship, stands up against his comrades.. This pivotal moment showcases Koby's growth as he defies the expected norms of a Marine and stands up for what he believes is right.

Redemption and Acceptance: Garp's Guidance

One Piece Vice Admiral Garp eavesdrops on Koby and Helmeppo as they talk about Luffy

Garp intervenes before the situation escalates further, revealing that he had been sleeping when Morgan attacked him. Helmeppo, having abandoned his father to escape, returns to the Marine ship and both he and Koby apologize to Garp.

However, Garp also overhears these two talking about Straw Hat Luffy, and hears them mentioning their relationship with the pirate. After confronting them with this, since Marines should not be friends with pirates, he challenges them both to a fight.

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Despite their initial feelings of worthlessness, they don’t give up, and their newfound comradery and friendship comes out to shine in this challenging situation. Garp surprises them by deciding to take them under his wing. However, their journey is far from over, as they are still required to perform janitorial duties while training intensively at their new headquarters. And things get really tough under Garp’s tutelage.

Riveting Character Development: Koby and Helmeppo's Evolution

One Piece Koby and Helmeppo fight Vice Admiral Garp

One of the standout aspects of the Diary of Koby-Meppo arc is the incredible character development of its protagonists, Koby and Helmeppo. At the beginning of the arc, Koby is portrayed as a dedicated and hardworking individual, while Helmeppo is depicted as arrogant and entitled. However, as the arc progresses, we witness their transformation and growth, defying our initial expectations.

Koby's unwavering determination and sense of justice shine through as he perseveres through the challenging tasks assigned to him. His commitment to his dream of becoming a Marine is unwavering, and it becomes evident that he possesses the qualities necessary to become a great asset to the organization. As Koby stands up against his fellow Marines to protect his friend, we witness a defining moment that showcases his newfound courage and willingness to go against the grain.

On the other hand, Helmeppo's journey is one of redemption and self-discovery. Initially driven by his father's position of power, he realizes the flaws in his ways and chooses to distance himself from his father's wrongdoings. Abandoning his father during Morgan's escape demonstrates his newfound independence and resolve to pave his own path. Helmeppo's growth serves as a testament to the power of personal introspection and the potential for change within oneself.

One Piece: The Diary of Koby-Meppo Arc

The Diary of Koby-Meppo: A Marine's Journey

One Piece Vice Admiral Garp reaches for a bag of cookies and smiles

The Diary of Koby-Meppo arc captivates readers with its engaging storyline and the transformation of its central characters. From their humble beginnings as janitors burdened with menial tasks to their growth as aspiring Marines, Koby and Helmeppo's journey is filled with moments of courage, loyalty, and redemption.

This arc serves as an excellent introduction to the world of One Piece, showcasing the themes of friendship, determination, and loyalty. The diary-like format allows readers to delve deeper into the characters' thoughts and emotions, enhancing the overall reading experience.

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The Diary of Koby-Meppo arc offers a compelling narrative and character development that will leave readers craving for more. While some may find the initial focus on chores and janitorial duties slow-paced, the arc quickly picks up with thrilling action sequences and significant character growth.

Coby's Dream: Becoming a Marine Admiral

One Piece Koby smiles with joy

Following one’s dreams is not meant to be easy, and even though Koby’s dream goes completely against one of his best friends and role model, Luffy. And even for Helmeppo, who now had to completely turn down the evil deeds of his father and decided to follow a path of justice and righteousness along with Koby.

With its blend of humor, suspense, and heartfelt moments, this arc is a must-read for One Piece fans and a promising start to the Arabasta Saga. So, grab your swords and set sail on this exciting adventure with Koby and Helmeppo as they strive to become Marines and uncover the secrets that lie ahead in the world of One Piece!

Overall Score: 7.5/10

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What is the Diary of Koby-Meppo Arc about?


What episodes are the Diary of Koby-Meppo arc?


Is the Diary of Koby-Meppo arc filler?


Who is Coby?


Who is Helmeppo?


Why does Garp decide to train Koby and Helmeppo?


How does Coby get so strong?



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