The Straw Hat Pirates are the main cast of One Piece. Led by Luffy, this crew hails from the East Blue and has made its presence known in the mightiest of seas in the world. The entire story of One Piece is centered around the Straw Hat Pirates, and thus, fans know quite a lot about this group already.

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However, every member of the crew still carries mysteries that the author has not yet fully revealed. These mysteries are quite intriguing, with some relating to the past of the crew members while others having key knowledge that is crucial to the overarching plot of the series.

10 Jinbe's Knowledge On Nika

One Piece Jinbe

During the Wano Country arc, Jinbe fought against Who's Who of the Beast Pirates. While much of the fight played in Jinbe's favor, fans got to experience great action from both the fighters.

That certainly wasn't the most important part of the fight, however. Interestingly, Who's Who mentioned a figure called Nika who existed long ago during the Void Century and was worshipped by slaves. Who's Who attempted to gain knowledge on Nika from Jinbe but didn't get an answer from the helmsman due to his racist nature.

9 Brook's Past Kingdom

brook-binks-sake

Brook is the oldest member of the Straw Hat Pirates and has had quite an adventure on the seas already. Before sailing with Luffy, he was stuck in the Florian triangle for 50 years, and even before that, he served as the Captain and the musician of the Rumbar Pirates.

Interestingly, however, even before that, Brooke was the leader of a battle convoy of a certain kingdom. So far, Oda has not revealed what kingdom this was and how it ties to Brook's origins.

8 Franky's Parents

Young Franky Trying To Stop The Puffing Tom

Franky was introduced to the fans during the Water 7 arc where he ended up becoming their shipwright. During his flashback, it was revealed that Franky was adopted by Tom at a very young age.

Franky actually heals from South Blue and was abandoned by his parents, both of which were pirates. So far, it's not been revealed who his parents were and if they still sail the waters of the One Piece world.

7 Robin's Dad

Close up of Nico Robin during One Piece Episode 1000

Robin's flashback is widely considered to be one of the very best in One Piece. Fans got to witness the harsh childhood that Robin went through and how she was abandoned by her mother for the sake of the Poneglyphs.

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Curiously, no mention of Robin's father was made in the flashback. It is unknown if he's alive or whether or not Robin even knew him.

6 Chopper's Rumble Balls

Chopper is the doctor of the Straw Hat Pirates and he joined the crew during the Drum Island arc. He's an exceptionally skilled doctor and it certainly wouldn't be a stretch to say that he's already the best in the world. Chopper has also developed certain drugs that are quite useful, such as the Rumble Ball.

By eating this drug, Chopper can access his many transformations, the strongest of which is the Monster Point. However, it is not yet known how Chopper came up with it and how it affects standard Zoan Devil Fruits. Whether or not this ball will work on someone like Luffy, who is also a Zoan, remains to be seen.

5 Sanji's Powers

Sanji fights against Jabra

Sanji is the cook of the Straw Hat Pirates and his aim is to find the All Blue, a miraculous sea that exists somewhere in the Grand Line. Along with being a cook, Sanji is also one of the three strongest combatants of the crew. His ability, called Diable Jambe, sees him light his feet on fire and attack with this increased speed and weight.

How exactly Sanji manages to do this remains unknown, however. During the Wano Country arc, Queen hinted that no normal human can combust into flames unless they are Lunarian. Whether this will come into play in the story later or not remains to be seen.

4 Usopp's Lineage

Usopp (One Piece)

Usopp made his debut in One Piece's Syrup Village arc. Fans got to see him join the crew by the end of the arc and he established a dream of becoming a great warrior of the sea shortly after. What's more, Usopp is commonly known as a liar and has drawn connections to the likes of Montblanc Noland quite often.

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Usopp's last name is also unknown so far, which is quite curious. It is entirely possible for him to be related to Noland somehow and this could well be revealed later on in the story.

3 Nami's Origins

Nami Clima-Tact (One Piece)

The navigator of the crew, Nami officially joined Luffy during the Arlong Park arc. In her backstory, it was revealed that she was found by Nojiko and they were both eventually adopted by none other than Bellemere.

To this day, it isn't known where Nami actually comes from. Her past could well end up becoming relevant in the story moving forward.

2 Zoro's Origins

Roronoa Zoro And His Three Swords (One Piece)

Zoro was the first person to join Luffy on his journey to becoming the Pirate King. It is known that Zoro hails from Shimotsuki Village in the East Blue. However, as made clear in the Wano Country arc, he bears quite a resemblance to those of the Shimotsuki Clan, such as Ushimaru, and even Ryuma to quite an extent.

Zoro certainly has ties to Wano Country and, most likely, his parents or grandparents lived there. So far, however, the truth of this has not been revealed to the fans.

1 Luffy's Mother

Luffy Eating The Gum-Gum Fruit

Luffy is the protagonist of One Piece and the captain of the Straw Hat Pirates. Being the focus of the story, the majority of mysteries about him have already been answered to the fans. However, the mystery of his mother still remains.

While fans do know that Dragon is Luffy's father, his mother, who Oda confirmed is alive and well, has not made an appearance just yet. In the future, more of Luffy's past could be revealed to the fans when she makes her appearance.

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