Neptune

Biodata

Feature	Value
Name	Neptune (尼普顿)
Alias(es)	Lord Neptune; Great Knight of the Sea
Species/Race	Coelacanth merman
Gender	Male
Affiliation	Ryugu Kingdom; Fish-Man Island
Occupation/Role	King of the Ryugu Kingdom
First Appearance	Chapter 13

Background / History

Neptune rules the Ryugu Kingdom, Fish-Man Island’s sole established government, from Ryugu Palace. He has built connections with influential figures over the years, including the Roger Pirates, Whitebeard, and King Harald of Elbaf. 15 31

When Shyarly foresees Fisher Tiger’s death and a looming crisis for Fish-Man Island, Neptune recognizes that his kingdom lacks the true powerhouses needed to withstand the Great Pirate Era. He initially considers paying Whitebeard to protect Tiger, but Mobius persuades him to pursue a lasting trade-and-protection partnership instead. 17

Impressed by Mobius’s plans for Fish-Man Island’s development, Neptune appoints him national preceptor and accepts his Naval Science Unit affiliation. He later moves to publicly recognize Mobius as the kingdom’s national advisor. 18 21

After the clashes involving Kaido, Whitebeard, Harald, and the Charlotte Family damage Fish-Man Island, Neptune continues working with Mobius, Whitebeard, Harald, Shakky, and Fisher Tiger to build alliances, receive liberated slaves, and develop the kingdom’s resources. 31 36 39 40

Appearance

Neptune is an enormous coelacanth merman, described as being as massive as a giant. 13

• Long, curly orange hair and beard. 13
• Large, furry orange face. 39
• Keeps a whale as both a pet and mount. 13

Personality

Neptune is compassionate, softhearted, and deeply concerned for the safety of Fish-Man Island and its people. The long history of persecution against fish-men and merfolk made him wary of humans and reluctant to seek a place on the surface, but Mobius’s plans give him a practical reason to change. 17 31

He is trusting once he accepts someone’s sincerity. He accepts Mobius despite his Navy affiliation, maintains friendships with figures such as Whitebeard and Harald, and supports plans that could let his people trade, work, and eventually reach the surface. 18 31 37

Neptune is also prone to relying on more strategically minded allies. He repeatedly seeks Mobius’s guidance on Fish-Man Island’s future, yet readily commits the kingdom’s resources once a plan convinces him. 17 31 40

Abilities & Skills

Leadership and diplomacy

Neptune governs Fish-Man Island and can commit the Ryugu Kingdom’s treasury, ships, military, and resources to major initiatives.

• Offered protection to Fisher Tiger despite the danger posed by the World Government’s wanted notice. 17
• Agreed to develop trade routes and a long-term partnership with Whitebeard rather than merely purchasing protection. 17
• Joined Harald, Whitebeard, and others in efforts to make Fish-Man Island accepted by surface nations. 31 36
• Authorized a census and settlement program for liberated slaves, including the identification of skills for future employment. 40

Combat awareness

Though not presented as one of the sea’s foremost combatants, Neptune is a renowned figure on Fish-Man Island and can sense dangerous clashes nearby. 20

• Detected the threat generated by Mobius and Jinbe’s sparring match from his bedroom in Ryugu Palace. 20
• Was incapacitated by the overwhelming Haki released during the conflict involving Kaido and the Charlotte Family, but suffered no lasting injury. 30

Relationships

• Queen Otohime — Wife and queen of the Ryugu Kingdom. They jointly support Fish-Man Island opening toward the surface and sheltering liberated slaves. 16 39 40
• Shark Star, Ryuboshi, Manboshi, and Shirahoshi — His children. Neptune is proud of them and introduces them to Mobius during a banquet. 18
• Jinbe — Leader of Neptune’s Army and Fish-Man Island’s greatest warrior. Neptune trusts Jinbe’s loyalty and relies on him for protection and escort duties. 16 21 31
• Fisher Tiger — A fish-man Neptune greatly admires and wishes to protect after Tiger’s attack on Mary Geoise places Fish-Man Island in danger. 17 39
• Mobius — National preceptor and national advisor. Neptune trusts Mobius’s political and economic plans, despite knowing he belongs to the Navy. 18 21
• Whitebeard (Edward Newgate) — Old friend and prospective trade-and-protection partner for Fish-Man Island. 17 31 33
• Harald — Old friend and King of the Giants. Neptune asks for Harald’s help in gaining surface-world acceptance for Fish-Man Island. 31
• Shyarly — A diviner whose prophecies Neptune takes seriously; he grants her immediate access to Ryugu Palace. 16 17

Story Role / Major Arcs

Fish-Man Island prophecy

Neptune receives Shyarly’s warning that Fisher Tiger will die and that Fish-Man Island faces a severe crisis. This forces him to confront his kingdom’s vulnerability despite its location ten thousand meters beneath the sea. 17

Appointment of Mobius

After hearing Mobius’s proposal for trade with Whitebeard’s territories, Neptune appoints him national preceptor and entrusts him with helping develop Fish-Man Island. 18

Defense of Ryugu Palace

Neptune witnesses Mobius’s superiority over Jinbe in their sparring match and becomes still more convinced of his advisor’s value. During later conflicts, he shields Otohime and their children with his own body while unconscious from Haki pressure. 21 30

International alliance-building

Neptune works with Mobius, Whitebeard, Harald, Shakky, and later Fisher Tiger toward cooperation among Fish-Man Island, the Whitebeard Pirates, Elbaf, and Kuja Island. 33 36 39

Settlement of liberated slaves

Neptune opens the royal treasury and provides food, medical care, housing, ships, and administrative support for slaves liberated from Mary Geoise. He also implements Mobius’s census proposal to identify their backgrounds and skills. 40