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Ryuboshi is an oarfish merman and the second son of the royal Neptune family on Fishman Island.


He is an extremely tall and thin merman (shown when he spoke with Madam Shyarly), and is the tallest of his brothers. He has wide eyes, long wavy dark pink  hair, and beaverlike teeth.[1]

The only one of the princes to be clothed in the upper body, he wears a fancy robelike garment with sleeves that are puffed at the shoulders and wrists. He carries two swords behind him, held in place by an orange sash. He also has a long purple tail with white polka dots and a red fin.[1]


Ryuboshi is very upbeat and jovial. He has a habit of ending his sentences by singing part of a musical scale, such as "so-la-ti-do". He and his younger brother Manboshi apparently like to dance, as he suggested it to him while Fukaboshi was asking the mermaids about the Straw Hat Pirates. His habit of dancing came from his effort to cheer his sister up to protect Fishman Island from her powers.[1]

However, he can be serious if the situation calls for it, such as when Luffy was beating up the New Fishman Pirates, he started to draw his sword, should his involvement have become necessary.

Abilities and PowersEdit

As a prince, he has some royal authority over Fishman Island. Hammond referred to Ryuboshi and his brothers as three of the most powerful people in the Neptune army, implying he has great fighting prowess. The Minister of the Right claimed that the Straw Hats would be in trouble if they are confronted by the brothers. Further testament to their strength is when the three brothers alone took down the sea beasts that easily felled the rest of the Neptune Army including the two ministers and the fact that the New Fishman Pirate Officers had to take at least two Energy Steroids to defeat him and his brothers.


Further information: Merman Gujutsu
Ryuboshi With His Swords

Ryuboshi weilding his two swords.

He carries two long rapiers, with katana-wrappings around their hilts and prominent handguards. Their plain sheaths are crossed behind his lower back. He has proven himself to be a master swordsman, dispatching a group of gigantic sea monsters enhanced by drugs in mere seconds, with the aid of his two brothers.



Ryugu Royal Family

Ryuboshi and his siblings after their mother returned home from preaching.

As a child, he would look after Shirahoshi with his brothers whenever their mother, Otohime was away preaching to the kingdom's citizens.[3]

When Shirahoshi was six-years-old, a World Noble arrived on the island in a wrecked ship. Otohime quickly dashed off to where the ship was docked. The four children of the royal family soon followed her.

When Otohime was threatened by the noble she was protecting, Shirahoshi cried and unknowingly called out Sea Kings. The World Noble has passed out from a big shock and Ryuboshi and his brothers tried to calm Shirahoshi.

Ryuboshi and his siblings seemed worried when Otohime decided to accompany the noble to the surface. For one week, they anxiously waited in the castle for her return. After Otohime returned safe and sound, she finally reached out to the citizens and collect their signatures. Ryuboshi, his siblings, and Neptune were overjoyed by Otohime's success.

Otohime later explained to Ryuboshi and his brothers about Shirahoshi's ability to call Sea Kings which is connected to a legend. She went on saying that Shirahoshi's ability could be dangerous since she could not control it yet. Otohime then asked the three brothers to become strong warriors and protect Shirahoshi.

Manboshi and Ryuboshi Try to Cheer Shirahoshi Up

Ryuboshi dancing and singing with Manboshi in spite of their mother's death.

One day in Gyoncorde Plaza, the box containing all of the signatures suddenly caught fire. In the confusion, Otohime was shot. Ryuboshi and his brothers immediately came to their mother's side. The three brothers tearfully listened to their mother's last words, telling them not to be angry for her sake and to look after Shirahoshi. They then noticed that Shirahoshi was about to scream. Ryuboshi and Manboshi remembered what their mother said about what could happen if Shirahoshi calls Sea Kings again and how an emotional shock could trigger it. The two brothers then started singing and dancing in a desperate attempt to raise Shirahoshi's spirits and keep her from crying out, much to everyone's confusion and annoyance. As their mother passed away, Ryuboshi and his siblings touched pinky fingers with her for the last time.

Before Otohime's funeral, the four children of the royal family told their father, Neptune, about the love letters that kept flying to Shirahoshi. Neptune told Ryuboshi and his siblings to not to go out to the funeral since danger still lurked around. During Otohime's funeral, Ryuboshi and his siblings were seen on a visual broadcast as Fukaboshi gave his speech.

Fishman Island ArcEdit

Meeting the Straw HatsEdit

Merman Gujutsu Infobox

The brothers take down the sea beasts.

He first appeared in Mermaid Cove along with his brothers Fukaboshi and Manboshi, looking for Luffy because of his illegal entry. The mermaids hid the crew, but Sanji had a massive nosebleed and blew their cover. After Keimi, Luffy, Usopp, Sanji, and Chopper escaped on the royal gondola that the three princes were riding on, Ryuboshi explained with his older brother that they were looking for the Straw Hat Pirates for a reason other than their illegal entry. They had to give them a message from Jinbe.

He was later seen in Coral Hill, along with his brothers, looking concerned about Madam Shyarly's prediction.

He was then seen outside the palace bubble, waiting to be let in. He was shocked when he realized that the Straw Hat Pirates caused some kind of incident in the palace. Sometime later, he and his brothers watched Hody's speech to Fishman Island, where he explained his plan to recreate the Ryugu Kingdom with himself as the ruler. Ryuboshi was shocked and worried when Hody showed the chained-up king.

After Hody finished his speech, Ryuboshi and his brothers all rode on their gondola and headed for Gyoncorde Plaza to save their father, who was scheduled to be executed by Hody himself. While traveling, Ryuboshi wondered if Shirahoshi was safe.

Battle for Fishman IslandEdit

He soon arrived at Gyoncorde Plaza with his brothers and declared that the Neptune Army would not be defeated so easily. He then tells Neptune to wait a little longer. As the three princes are fighting the sea monsters, Ryuboshi told Hody that if he wins, fishmen would never be able to walk beside humans even if a century came and went. After defeating the sea beasts, Ryuboshi and his brothers then charged at Hody and the officers.

Gyoncorde Plaza Execution

Ryuboshi with his father and brothers, all chained up and on display for execution.

Initially, the princes had the upper hand, but the officers turned the odds against them by taking Energy Steroids. The princes were then defeated and captured. After Shirahoshi, Megalo, and Jinbe were captured and brought to the plaza, Hody revealed to everyone that he was the one who truly killed Otohime. Ryuboshi was stunned at this revelation. Shirahoshi said that she already knew about it thanks to Megalo and she did not tell anyone because she was honoring her mother's last wish of holding no hatred for the killer. As Hody mocked Shirahoshi for allowing him to go free, he attacked the royal brothers and Neptune with Yabu Same. Ryuboshi, along with his father and brothers, were then rescued by Hoe during the Straw Hats' unexpected arrival.

Ryuboshi and his brothers later recovered when Noah (thrown by Decken towards Shirahoshi) arrived at Fishman Island. When Shirahoshi swam away from Fishman Island, Ryuboshi and his brothers went after her. Ryuboshi and Manboshi came to their sister's aid at the moment Decken threw some knives at her. After saving Shirahoshi from death, they tried to lead Shirahoshi to safety.

Hody then went to Decken and stabbed him with his trident. Ryuboshi and Manboshi were confused since Hody and Decken were supposed to be allies. Hody then went after Shirahoshi and repelled both Ryuboshi and Manboshi. Luckily, Fukaboshi and Luffy arrived just in time to stop Hody. Hody later explained what would happen if Decken dies while the ship Noah is directly above Fishman Island. Once Decken's power loses its effects, the ship will fall on the island. Understanding the situation, Ryuboshi told Shirahoshi to change her course to the side.

Unfortunately, Decken fell unconscious and the ship started falling towards Fishman Island. Luffy later defeated Hody and the Sea Kings stopped Noah from falling.

Restoration of PeaceEdit

Now that the island was saved from destruction, Ryuboshi and his brothers then took the unconscious Hody and Decken to the plaza and put them in chains. While the officers and Vander Decken IX were imprisoned, the royal family and the Straw Hats had a feast at Ryugu Palace as a celebration. Later, when the New Fishman officers turned old due to the Energy Steroids, Ryuboshi went down to the dungeon with his father, brothers, Jinbe, and the ministers and saw that the imprisoned officers have become old men.

Afterwards, Ryuboshi and the people of Fishman Island bid the Straw Hats farewell as they set sail for the New World. Ryuboshi and his brothers expressed their gratitude and promised their father that they would not forget the debt they owe to the Straw Hats.

Whole Cake Island ArcEdit

As the time for Reverie approached, the Neptune Family prepared to go to the surface. When Shirahoshi was too scared to come, Ryuboshi asked Neptune if they could leave without her.[4]

Major BattlesEdit

Non-Canon BattlesEdit

  • Ryuboshi and Manboshi vs. New Fishman Pirates


  • His name comes from ryūgū-no-tsukai (リュウグウノツカイ?), which is Japanese for "oarfish."


  1. 1.0 1.1 1.2 1.3 One Piece Manga and Anime — Vol. 62 Chapter 609 and Episode 528.
  2. One Piece Blue Deep: Characters World (p. 202), Ryuboshi's birthday is given
  3. One Piece Manga and Anime — Vol. 63 Chapter 624 (p. 6) and Episode 544, Ryuboshi looked after Shirahoshi.
  4. One Piece MangaChapter 823.

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Fishmen: Arlong  •  Hatchan  •  Chew  •  Kuroobi  •  Pisaro  •  Kaneshiro  •  Take  •  Shioyaki  •  Octopako  •  Jinbe  •  Hammond  •  Kasagoba  •  Hody Jones  •  Fisher Tiger  •  Ammo Knights  •  Dosun  •  Zeo  •  Daruma  •  Ikaros Much  •  Harisenbon  •  Junan  •  Papaneel  •  Togare  •  Gotan  •  Nuru  •  Tom  •  Hack
Merfolk: Keimi  •  Hyouzou  •  Medaka Mermaid Quintuplets  •  Ishilly  •  Kairen  •  Hiramera  •  Seira  •  Mero  •  Lulis  •  Adele  •  Fillonce  •  Sora  •  Fukaboshi  •  Ryuboshi  •  Manboshi  •  Shyarly  •  Neptune  •  Minister of the Right  •  Minister of the Left  •  Shirahoshi  •  Den  •  Aladdin  •  Otohime  •  Maria Napole  •  Luca  •  Meverly  •  Garcia
Animals: Pappug  •  Hoe  •  Megalo  •  Surume  •  Daidalos
Fighting Style Based: Fishman Karate (Fishman Jujutsu)  •  Merman Combat  •  Merman Gujutsu  •  Rokutoryu  •  Hattoryu
Weapon Based: Kiribachi  •  Kirisame
Others: Haki  •  Energy Steroid  •  Bubbly Coral
Related Articles
Story Arc(s): Fishman Island Arc  •  Whole Cake Island Arc
Locations: Ryugu Kingdom  •  Ryugu Palace  •  Mermaid Cove  •  Coral Hill (Mermaid Cafe)  •  Gyoverly Hills  •  Sea Forest  •  Criminal Brand Company  •  Fishman District  •  Fishman Karate Dojo  •  Candy Factory  •  Gyoncorde Plaza  •  John's Candies Shop
Ship(s): Noah  •  Ryugu
Organizations: Shichibukai  •  Sun Pirates  •  Arlong Pirates  •  Macro Pirates  •  New Fishman Pirates  •  Flying Pirates  •  Big Mom Pirates  •  Whitebeard Pirates
Others: Slavery  •  Edward Newgate  •  Charlotte Linlin  •  Tamatebako  •  Mermaid Princess (Poseidon)
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Titles: King  •  Queen  •  Princess  •  Prince
Royal families: Nefeltari Family  •  Gorgon Sisters  •  Riku Family  •  Donquixote Family   •  Kozuki Family  •  Vinsmoke Family
Nobles (canon)
Alabasta: Nefeltari Cobra  •  Titi   •  Nefeltari Vivi
Amazon Lily: Boa Hancock  •  Boa Sandersonia  •  Boa Marigold  •  Gloriosa 
Black Drum Kingdom: Wapol  •  Miss Universe
Goa Kingdom: Stelly  •  Sarie Nantokanette
Ryugu Kingdom: Neptune  •  Otohime   •  Fukaboshi  •  Ryuboshi  •  Manboshi  •  Shirahoshi  •  Poseidon 
Dressrosa: Donquixote Doflamingo   •  Riku Dold III  •  Scarlett   •  Viola  •  Rebecca   •  Kyros *
Tontatta Kingdom: Gancho  •  Mansherry
Mokomo Dukedom: Inuarashi  •  Nekomamushi
Others: Thalassa Lucas  •  Dalton  •  Goldfish Princess  •  Bellett  •  Emporio Ivankov  •  Elizabello II
Nobles (non-canon)
Crown Island: Kirin Lion   •  Mobambi
Mecha Island: Ratchet  •  Roba
Others: Musshuru  •  Caroline

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