Neptune

King Neptune (ネプチューン王) is a Coelacanth merman and the king of the Ryugu Kingdom on Fishman Island. He is the father of Fukaboshi, Ryuboshi, Manboshi, and the Mermaid Princess.

Appearance
Neptune is a large, muscular, and hairy Coelacanth merman. He has long curly hair and a curly beard and a darkened nose. As king, he wears a crown that resembles a tulip and carries a trident. He has matching tattoos on both arms.

Personality
He appears to be very protective of his family, as he had his sons form an army solely to track down Vander Decken IX so that the pirate would stop harassing his daughter. He also seems to be very blunt, as he simply invited the "Strawhat humans" to the Ryugu Palace, instead of being more cordial.

Abilities and Powers
As king, he has royal authority over the entire Ryugu Kingdom. Whether he has any fighting ability is unknown. However, his presence outside the palace is enough to cause a commotion with the inhabitants referring him as "You-Know-Who".

While he is the king of Fishman Island, he has had to rely on the protection of two of the Yonkou: Whitebeard until his death and then Charlotte Linlin (Big Mam) afterwards. He didn't have to pay collateral to Whitebeard, but he does have to pay a monthly fee of sweet candy to Big Mam.

History
He was so angered by Vander Decken IX pestering his daughter through letters, packages, and ultimately marriage proposals, that he had his three sons form an army called the Neptune Army to capture him.

When he learns that Straw Hat Luffy is in Pappug's mansion, he personally travels there to meet him. After making contact with Luffy, King Neptune invites him and his crew to his palace.

Trivia

 * His name comes from Neptune, the Roman god of the sea.
 * His appearance is similar to that of Triton from Disney's "My Little Mermaid".