King Neptune
King Neptune is the ruler of the Ryugu Kingdom and a coelacanth merman identified as the sea god of the undersea realm. He leads the Neptune Army, extends formal invitations to visitors such as the Straw Hats, and confronts direct threats from Hody Jones aimed at seizing control of Fishman Island. Neptune is known for protecting his family members including Shirahoshi and the three Neptune brothers while upholding royal duties across multiple conflicts and diplomatic exchanges.
Throughout his rule Neptune maintains a trident as a constant symbol of authority, reacts to crises with both rage and strategic commands, and reflects on past battles and personal contradictions regarding revenge and peace. His actions include ordering evacuations, confronting intruders like Vander Decken, and later addressing mixed crowds after major defeats of opposing forces.
Appearance
Personality
King Neptune displays authoritative protectiveness by scolding visitors about kingdom dangers and ordering soldiers during evacuations. He prioritizes the safety of subjects over material treasures when deciding not to pursue stolen royal items after battles.34
Neptune reveals internal conflict over cycles of hatred after personal losses, locking himself away until murderous urges subside and admitting past guilt for not supporting peace efforts. He expresses regret regarding former comrades while affirming ongoing royal responsibilities.56
Neptune explains deep-seated fishman hatred toward humans and references past peace attempts blocked by humans while Luffy listens intently to the warning. He demands a petition for island relocation and notes distrust of humans while calling the situation a pickle.78
Neptune has locked himself in Shell Tower to control his rage and admits he wanted to kill the human culprit personally while expressing deep internal conflict over Otohime's death and revenge. He has previously killed humans in battle.9
History
Early encounters
Intrusions and evacuations
Aftermath of occupation
Royal duty
Neptune explains Joyboy as the man known as Joyboy who lived in the surface world during the Blank Century eight hundred years ago at least with the passage addressed to a mermaid princess who lived on Fishman Island at that time. He and his predecessors protected Noah for generations trusting that legend.15
Roger Pirates visit
Twenty years ago
Relationships
King Neptune maintains close ties with his sons Fukaboshi, Ryuboshi, and Mamboshi by sending them to greet visitors and leading them during evacuations and public addresses. He also protects his daughter Shirahoshi during direct confrontations with intruders.2021
Neptune extends invitations and reassurance to the Straw Hats while later thanking Luffy for preventing disaster and discussing potential alliances including the Straw Hat Jolly Roger as a protective flag.122
Neptune maintains ties with his sons as three Neptune brothers are labeled with name boxes at bottom of page and the brothers discuss escorting Shirahoshi. He demands release of the princess and references Ryugu Kingdom debt while his children beg father not to hate and wish for better future.232425
Neptune arrives on scene after Vander Decken's intrusion and chooses not to pursue the stolen royal treasures while multiple fishmen react with shock to Neptune's stance on the treasures. He shows momentary pity toward the prisoners.26
Major battles
King Neptune sustained multiple gunshot wounds while shielding servants from Hody Jones during an intrusion at the palace yet retained his trident and dismissed the attack as petty. He later faced chained defeat in the plaza where Hody Jones struck him and the princes with devastating force.2728
Neptune sustains multiple gunshot wounds while shielding servants from Hody Jones during an intrusion at the palace yet retains his trident and dismisses the attack as petty. An unknown attacker mocks Neptune for taking bullets meant for servants and questions his fitness for the throne with aggressive contempt.29
Neptune physically confronted Vander Decken with a drawn sword while injured and continued fighting alongside Luffy to reaffirm protection of Shirahoshi. He later ordered the army into the plaza to aid allies against the New Fish-Man Pirates using gunfire.3031
Neptune attempts to retrieve Shirahoshi from the conflict and launches a direct physical attack on Charlos while his children attempt to calm their father during the clash. He demands Shirahoshi be returned and declares intent to return to the sea floor while affirming yes firmly and ordering CP0 killed.3225