Eiichiro Oda's One Piece follows the adventures of Luffy and his Straw Hat Pirates as they travel across the seas to attain the greatest treasure, the One Piece. On their journey, the Straw Hats have gradually been growing stronger , evolving into the menacing pirate crew that they are today. However, they weren't always this powerful.

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Some of the Straw Hats, along with many other characters sailing the seas of One Piece, started off rather weak—  and their struggles made them shine in the later arcs of the series.

10 Helmeppo Was A Spoiled Child In Shells Town

Helmeppo with his visor in One Piece

Helmeppo was introduced to the fans in One Piece's Shells Town arc, where he played the role of a minor antagonist. Thanks to his father, he was able to get the Marines to do his bidding and exploit the weak, but after getting beaten by Luffy and Zoro, Helmeppo mended his ways and worked to help people as a part of the Marines. Once weak, Helmeppo is now quite strong. He's currently a lieutenant of the organization thanks to his training under Vice-Admiral Garp.

9 Koby Aims To Become An Admiral Of The Marines In The Future

One Piece Koby

Koby was once a member of Alvida's pirate crew, but mainly because he was kidnapped by her men while he was fishing. Evidently, Koby was pretty weak back in the day. After joining the Marines, though, he's proven himself to be useful.

Under Garp, Koby has become more powerful and can now hold his own against most of his enemies. He's acquired the power of the Rokushiki and knows how to use Observation Haki as well. It's easy to see that Koby has come a long way.

8 Buggy Was Just An Apprentice On Gol D. Roger's Ship

Shanks and Buggy One Piece

Buggy the Clown is one of the most infamous pirates in the world of One Piece. Prior to the Reverie, he was one of the Shichibukai, thanks to his reputation as a member of the Roger Pirates and a sworn brother to the Yonko Red-Haired Shanks.

But Buggy wasn't always as great as he is today. Back in the day, Buggy was merely an apprentice on the Oro Jackson and appeared to be a coward, unlike Shanks. Since then, he's done more to make his presence known.

7 Trafalgar Law Had No Skill As A Fighter During His Childhood

Trafalgar Law One Piece

Law was once a citizen of North Blue's Flevance, also known as the White City, which was later completely destroyed due to the White Lead Disease. The only known survivor, he somehow made it to a neighboring country and found his way to Donquixote Doflamingo.

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At this point, Law was quite weak and had no skill as a fighter. However, his will to watch the world burn is what pushed Doflamingo to take him under his wing and train him to become the strong pirate that he is today.

6 Momonosuke Is Weak But Possesses Tremendous Potential

momonosuke oden, The Rightful Leader Of Wano

Momonosuke is Kozuki Oden's son and a proud samurai of Wano Country. Introduced during the Punk Hazard arc, Momonosuke was revealed to have eaten an artificial Devil Fruit made by Vegapunk from Kaido's lineage factor. As such, he possesses the ability to turn into a dragon at will. Although he started as weak, he's grown a lot since then and thanks to Shinobu's power, could become even stronger as he gets older.

5 Chopper Was A Simple Reindeer Before Eating His Devil Fruit

One Piece Chopper Rumble ball

Chopper is a reindeer once, ostracized by his herd for his blue nose. At some point in his life, he ate a Devil Fruit and gained the ability to turn into a human at will.

Although Chopper was fairly weak at first, he gained a lot of knowledge and developed a drug known as the Rumble Ball, which grants him several transformations. Chopper gained tremendous power to protect those he loves and continues to grow stronger today. In Wano Country, he managed to extend the duration of the Monster Point from 3 minutes to 30 minutes.

4 Sanji Was Branded As A Failure By His Biological Father, Vinsmoke Judge

Sanji Vinsmoke Mr. Prince One Piece

Sanji is the Straw Hat Pirates' chef and a member of the Monster Trio as well, making him one of the most fearsome pirates in the entire world of One Piece. Interestingly, Sanji wasn't always that much of a threat. Unlike his siblings, Sanji didn't gain any special powers from Judge's experiments on him, thanks to his mother.

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While the others grew stronger, Sanji remained weak; all he liked to do was cook and, at times, feed rats. Sanji eventually ran away from home and ran into Zeff, who saved his life and taught him how to fight.

3 Nami Excelled Only In Stealing From Pirates Back In The Day

Nami laughing and holding up three fingers in One Piece.

The Straw Hat Pirates' navigator, Nami is an incredibly powerful pirate currently. She started her journey as a pirate after the events of the Arlong Park arc, however, fighting was certainly not her forte at first.

Slowly, she incorporated her knowledge of weather into her Clima-Tact and gained impressive abilities. With time, she grew to be a pirate capable enough to take on the likes of Ulti of the Tobiroppo in battle and win. In the future, Nami is bound to grow even stronger and become a fearsome pirate of the new era.

2 Usopp Was Once Just A Coward From Syrup Village

Usopp & Kaya Together

Usopp is currently a man worthy of being called the sniper of the Straw Hat Pirates, but that wasn't always the case. Much of Usopp's early life was spent lying to Syrup Village's people, and in fights, Usopp used to be a coward.

After joining Luffy, he has certainly changed for the better. Usopp is one of the bravest characters in the entire story. He's grown to be one of the only five people capable of using Haki in the Straw Hat Pirates, which is incredibly impressive given where he started.

1 Luffy's Devil Fruit Demanded Intense Training

Luffy As a Kid One Piece

Luffy is the captain of the Straw Hat Pirates with a bounty currently worth 1.5 billion Berries. He's earned the title of "The Fifth Emperor of the Sea," which just goes to show how renowned he's become in the One Piece world.

However, much like many of his crewmates and allies, Luffy was once weak. His Devil Fruit made him even weaker as it was incredibly difficult for him to control his powers as a kid. Thanks to the relentless effort that he put in, he was able to grow up into a terrific pirate.

NEXT: 10 Best Life Lessons One Piece Has Taught Fans (So Far)