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 Shirahoshi, and the husband of the late Queen Otohime.

Appearance
Neptune is a giant-sized and muscular coelacanth merman. He has a red nose, small eyes, and long thick orange curly hair and beard. Both his chest and arms are covered with hair. He is bare-chested and has matching black tattoos on both arms, which looks like a spiral with wavy protrusion designs around it.

As king, he wears a gold crown that resembles a tulip with jewels embedded, a golden bracelet on each wrist, and carries a gold trident with an elaborate design.

At Otohime's funeral, he wore a large suit.

Personality
Neptune seems to be very blunt, as he simply invited the "Straw Hat humans" to the Ryugu Palace, instead of being more cordial. He also tends to shout his words out for no reason, including a habit of shouting his own name at random times, being followed by his whale shouting "Hoe". Neptune sometimes mispronounces people's names, as he refers to Zoro as "Zori". He appears to be easy-going, absent minded, and carefree as he was scolded by his ministers for leaving the castle on a whim on more than one occasion. In the anime, he finish his sentences with jamon.

However, he can be serious when the situation demands it, as he intended to capture the Straw Hat Pirates when they were wrongly accused of kidnapping mermaids, though Neptune did not think it was fair to arrest them based on a prediction made by Madam Shyarly, and merely wanted to capture the crew rather than arrest them for a precaution. In addition to being fair, while in his youth he would kill others for revenge, in the present he has shown to be very merciful, as he allowed the human slaves of the New Fishman Pirates to leave and let the lower fishman subordinates to do penal work under the watch of the army.

He dotes on his only daughter Shirahoshi, and worries about her immensely. He provided several extreme but necessary security measures to protect her from Vander Decken IX, and even attempted to beg the Straw Hats to rush to her aid when he thought that his daughter is in danger. Neptune apparently acknowledges the value of sacrifice, as he decided that he would rather risk his daughter's safety in the hands of strangers than in Decken's captivity. He gets quite upset when he hears that Shirahoshi is upset and gets very emotional when she is in danger as shown when he burst into tears when Shirahoshi was supposedly kidnapped and when Decken went after her.

Neptune is also partially perceptive as he correctly guessed that Luffy snuck Shirahoshi out of Hard-Shell Tower by stuffing her inside Megalo, even though everyone else thought this was a bizarre idea. However, he can jump to conclusions when he stopped suspecting Luffy only after Vander Decken IX appeared in the palace and quickly accused Decken of kidnapping Shirahoshi.

He stated when his wife died, that even if the person who killed his wife was unarmed he would have torn them apart. However, moments later he noted Otohime would not approve of a revenge attack and though he would only have listened to those words because it came from her, he still couldn't understand why he could not bring himself to tear that person apart. He did not understand how the events led to the people of Fishmen Island and humans hating each other. He however, wanted to end the cycle of hate between humans, he noted due to his past as a soldier he could not be a candidate for causing such a thing as he would only cause the opposite of his intentions to happen. He understood how the circle continued though, that children who witness darkness only continue the dark path that has caused their problems, but time could heal those scars and pain.

Neptune is well aware of the Void Century and Poneglyphs, as well as the dangerous potential they pose to the world. Despite doting on his daughter, he knew she is the incarnation of the deadly ancient weapon, Poseidon, and fears of her power having fully awakened. He was also shocked and seemingly slightly frightened that Nico Robin is able to read about Joy Boy in the Sea Forest's Poneglyph, but trusted her enough to tell her about the history in detail when she asked.

Like many other characters in the series, he appears to have a unique laugh: Hoh hoh hoh hoh.

Family and Kingdom
Neptune 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 has a beloved whale named Hoe. The Ministers of the Left and Right tend to yell at Neptune for his lack of responsibility as the king of Ryugu Kingdom, and he doesn't seem to have any resentment to that. While Otohime was alive, Neptune supported her actions in promoting peace. Even ten years after her death, Neptune said he still loved Otohime and still considers himself married to her.

When he was tied up after his failed attempt to capture the Straw Hats, Neptune begged the pirates to ensure Shirahoshi's safety when he suspected that she might be in danger, showing great concern for his daughter, and warned the crew that if anything happened to Shirahoshi, he would hunt them down to the ends of the sea. Neptune considers Shirahoshi to be very precious to him. After Decken went after her, he begs the Straw Hats to stop Decken, going as far as to offer the crew anything.

As he is with his family, he also cares deeply about his subjects, going so far as to block an attack made by Hody Jones against his soldiers while they were tied up, despite being wounded as a result. Ironically, Neptune said earlier that he was willing to trade his soldiers' lives for Shirahoshi's safety. His affection is reciprocated by the civilians, who were even willing to see their kingdom destroyed (by Luffy in Shyarly's prediction) than allow Neptune to die in front of them.

Whitebeard
He was a personal friend of the Yonko, Whitebeard, as first shown when the Minister of the Left referred to him as Neptune's friend. Their friendship was the reason why the Yonko protected the island. Though it is unknown how they became friends, but it is known that they had been friends for quite long time as Neptune was said to have helped Whitebeard out a lot during his younger days; the two even shared a drink in the past.

Straw Hat Pirates
He respected the Straw Hats for saving his daughter's pet, Megalo, and invited them to a banquet as gratitude. However, Shyarly's prediction caused a conflict between him and the pirates. Neptune and his guards attempted to capture the pirates for the island's safety. The Straw Hats, in turn, resisted and ended up capturing Ryugu Palace instead. After the Straw Hats saved Neptune, his family, and his kingdom from Hody Jones, he has come to befriend them and cleared them of all crimes. He even allowed them to have all the treasures that were in the treasure room due to being indebted to them. Neptune remarked that he wishes to borrow their flag for the safety of Fishman Island in case it loses Big Mom's protection.

Jinbe
Neptune is a close friend of Jinbe as he's known him since when he was part of his army. Neptune was grateful towards Jinbe for joining the Shichibukai in an effort to support Otohime's quest for peace with humans. Even though Jinbe forfeited his title, Neptune still respects him and allows him to visit the island anytime he wishes. Neptune even encouraged Jinbe to consider joining Luffy's crew.

Vander Decken IX
Since Vander Decken IX kept harassing Shirahoshi with threatening marriage proposals, he has earned Neptune's wrath. Neptune had his sons form an army against the pirate. After Shirahoshi was believed to be kidnapped from the palace, Neptune quickly threw accusations at Decken after seeing him enter the palace just because he was after his daughter for ten years.

Hody Jones
Neptune's other enemy is Hody Jones, a fishman who strongly believes in vengeance against humanity. Hody believes that Neptune is unfit to rule Fishman Island because he (from Hody's perspective) lacks pride. Wanting to create a world where humankind is completely enslaved, Hody intends to overthrow him, going as far as to join Neptune's army only to gain battle experience, and then discarding his allegiance and disloyally launching a coup d'etat. Neptune berated Hody for overdosing on Energy Steroids, expressed disdain about his selfishness as the new king, and ultimately turned to a violent hatred after the former soldier revealed that he was the one who killed Otohime ten years ago. It appears that after Shirahoshi explained why she never told everyone the truth even though she knew about it, Neptune let go of that hatred and decided to just imprison Hody after his defeat. After seeing Hody turn into an old man due to the side effects of the Energy Steroids, Neptune takes pity on him and decides to possibly change his penal sentence.

Abilities and Powers
As the king, he has royal authority over the entire Ryugu Kingdom. His presence outside the palace is enough to cause a commotion with the citizens referring him as "You-Know-Who".

He seems to have an uncommon ability for a merman as he is able to communicate with whales; normally, they can only do so with regular fishes. He uses that ability to call his pet whale, Hoe, when he needs him.

As a former soldier himself, he was trained in military combat and was a veteran, although his prowess in his youth are mostly unknown. He is known to be extremely powerful in combat, being feared and respected as the "Great Knight of the Sea", but his strength seems to have weakened due to having sprained his back and general old age, which gave Zoro the upper hand. Neptune's sprained back also rendered him defenseless against the New Fishman Pirates when the pain incapacitated him after using one of his more powerful attacks.

He seems to be able to sense danger as he immediately took caution right after the New Fishman Pirates took Energy Steroids.

Merman Combat
He is shown using a technique called "Merman Combat". With it, he is capable of manipulating water, grabbing it with his hands as if it were something solid and launching water-based projectile attacks.

Weapons
He carries around a gigantic trident fitting his size, and is presumably proficient in using it, as Brook and many fishmen acknowledged his strength. Zoro, however, seemingly stopped one of his attacks with ease, and soon after managed to subdue Neptune and lock him in chains without receiving any visible injuries, although, according to Neptune, he was taken by surprise.

Early Life
In his early years, Neptune was a soldier who avenged the life of his fallen comrades and in the process killed and took prisoner many humans. At some point, Neptune became a close friend of Whitebeard when they both were in their prime.

The Time of Otohime and Fisher Tiger
While his wife, Otohime, was alive and preaching to the people of Fishman Island to unite with humans, Neptune told the Minister of the Left that he would not stop her from doing what she must and ordered the minister to protect her anyway he can.



When Fisher Tiger had a meeting with Neptune and Otohime after what seemed to be an adventure, Neptune asked Tiger about what he saw during his adventures. Tiger answered with one word, "humans". After news of Fisher Tiger's rampage in Mariejois reached the palace, Otohime told Neptune about the voice she heard from his heart, a voice raising a battle cry.

After Fisher Tiger's death, Neptune received a letter from Jinbe that explained the true story. Neptune comments that Tiger had lived the only way he could. Otohime tells him that she understood what his heart was saying the last time he visited the palace. Later, Jinbe visited the palace and spoke with Neptune about his invitation to join the Shichibukai. Jinbe told Neptune that accepting the position would help strengthen the bond between species and in some way, support Otohime's cause. Neptune agreed, saying it would cheer her up.

The Hope of Fishman Island
One day, an uproar occurred on Fishman Island when a World Noble named Mjosgard arrived on the island in a wrecked ship. The noble was spared from the fishmen's wrath and his wounds were treated. When Otohime wanted to travel to the surface with Mjosgard, Neptune objected, saying he would go in her place. Otohime told him that a weak person like her has to go with the noble in order to prove that the surface is safe for everyone. He let her go and waited for one week, trying to keep his children's spirits up.

Otohime returned safe and sound and she finally reached out to the citizens of Fishman Island and collected their signatures. Neptune and his children were overjoyed with her success. However, that excitement was short-lived as Otohime was later assassinated in broad daylight by Hody Jones.



Hody got away with the crime by placing the blame on a human pirate, leaving everyone on Fishman Island to believe that the human was the culprit. Neptune, feeling rage towards the human, locked himself in Hard-Shell Tower to keep his anger under control. As the Minister of the Left stood outside the tower, Neptune grieved over his wife's death. He was torn between love and duty. As a king, he wanted to honor Otohime's ambition and make peace with the humans. But as a husband, he wanted to tear apart the person who killed his wife.

Before Otohime's funeral, Neptune's children told him about the letters that kept flying to Shirahoshi. Neptune read one of the letters, which was a marriage proposal by Vander Decken IX. Neptune told his children not to go out to the funeral since threats still lurk around. Neptune attends Otohime's funeral in the Sea Forest and watched Fukaboshi's speech through a visual broadcast.

When Vander Decken IX started threatening Shirahoshi's life, Neptune became enraged that he had his three sons form an army to capture him.

Meeting the Straw Hats
When Shirahoshi's pet shark, Megalo, went missing (having been captured by the Kraken), Shirahoshi kept crying and crying and Neptune did not know what to do. Eventually, the shark returned to the palace.

When Megalo tells him about being freed by the Straw Hat Pirates, he looks forward to meeting them. 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.



The Straw Hats, Keimi, and Pappug rides on Megalo while Neptune rides on Hoe as he calls to them not to fall off. Neptune explains that Megalo is his daughter's beloved pet. She could not stop crying over how Megalo had not come home that Neptune didn't know what to do with her. He thinks about how dangerous fighting the Kraken must have been and thanks them for their great work. Luffy tells him that it was just a coincidence but he was glad to help. Neptune tells them that he had sent his sons out to get them, but when they didn't come back, he went out himself.

He says that he was excited for the banquet's menu and wanted to start as soon as possible. He then remembers that one of the Straw Hats was already at the palace. He had already started drinking and wouldn't listen when Neptune suggested it would be more fun for everyone to drink together. King Neptune says that he thought his name was Zori, and gets corrected with the right name. Neptune goes on to tell them that his soldiers will find all of the other Straw Hats and bring them to the castle.

Nami then asks Neptune a question about why Fishman Island is so bright despite being 10,000 meters below the surface. Neptune tells her that Fishman Island came to be when fishmen began living on the sea floor where there was light. He explains that the roots from a tree called Sunlight Tree Eve reach down to the sea floor and transfer light to Fishman Island. They approach the entrance of the palace. Neptune rings a doorbell, saying it is him, and a stammering voice says that they will open the gate at once. Once they are in the corridor beyond the gate, Neptune said "let's go", in excitement, shouting his own name as a battle cry. Luffy says that it looked like a cool palace with a lot of stuff. Neptune answers him bluntly saying of course it would as it is his castle. He then tells everyone to enjoy themselves.

Once inside the castle, two men instantly start berating Neptune for going out on his own. He tells them he will be sure to be more careful in the future. Everyone but Luffy watches this scene, realizing the king is getting yelled at and told off like a child. Neptune tells the men that he brought the people who saved Megalo from the Kraken. He also asks where his daughter, Princess Shirahoshi, is. The men tell him that "it" happened again just a moment ago. Neptune gets angry, telling the men they didn't set her up with the proper guarding to keep her from getting upset. One of the men retorts that the king disappearing during such a critical time would get the whole castle upset. He then lowers his head, apologizing and promising to take better care next time. The Straw Hats realize he is getting yelled at again. The two men who were berating the king are the Minister of the Right, a seahorse merman, and the Minister of the Left, a catfish merman. The Minister of the Right apologizes for berating the king in front of his guests, but they have something important to discuss with him. The Minister of the Left tells them they received a message from Fukaboshi.

The New Fishman Pirates' Coup d'État
After receiving word of the mysterious disappearances of the mermaids from Mermaid Cove and of Madam Shyarly's ominous prediction, the palace guards and personnel took action against the Straw Hats. After some of the guards are overwhelmed by Nami, Usopp, and Brook, The Minister of the Left begs Neptune to use his power against the pirates. Neptune doesn't wish to go against them just because of a prediction. He attempts to subdue the pirates, attacking with his large trident. Zoro intercepts him, blocking his attack with ease.



He is next seen chained up along with his ministers and the castle guards. He comments on how he has not been able to fight all that well after straining his back. He admits that he has gotten old and apologizes for being unprepared. Neptune's sons return, but they are stuck outside since the only way in the caste is the palace entrance. Zoro then speaks with Fukaboshi through Den Den Mushi while making some demands. Neptune informs Fukaboshi that he is speaking to the pirate who is worth 120,000,000. After Fukaboshi reveals Jinbe's message for Luffy and leaves to find the rest of the Straw Hats on Zoro's request, Neptune hears sounds coming from Shirahoshi's tower.

He realizes his daughter is in danger and asks if there are guards posted by her room. He is then told that they are all tied up with him. He then orders the Straw Hat Pirates to go and make sure Shirahoshi is safe. When the guards protest, Neptune tells them that dire situations call for sacrifice. He then angrily tells the Straw Hats to go to the northeast part of the palace where the tower is located. When Zoro asks why they should take orders from a hostage, Neptune becomes even more angry, telling them that if anything happens to his daughter while he is incapacitated, he would chase the pirates to the ends of the ocean.

Brook and the Minister of the Right then go straight to Shirahoshi's room and find her missing, having already left with Luffy and Megalo. When they inform Neptune about this, the king looks stunned. He then starts crying out and demands that the Straw Hats return Shirahoshi. Usopp yells back saying that they didn't kidnap the princess. Brook points out that he only saw Luffy and Megalo leave Shirahoshi's room. Neptune correctly guessed that Shirahoshi has been stuffed into Megalo, even though everyone else thought his idea was preposterous. The palace guards laugh at this statement saying that it is way too bizarre.

When Hody Jones and Vander Decken IX arrive at the palace, King Neptune quickly accuses Decken of kidnapping the princess. This makes Decken realize that Shirahoshi has left the palace and he quickly goes after her. Neptune then tearfully begs the Straw Hats to stop Decken, going as far as to offer them anything. Hody Jones then crushes a palace wall, flooding the palace in the process. Jones then launches his Archer Shark attack. Neptune protects some of his soldiers by taking some of the hits. Zoro then cuts his chains, saying that their deal with the hostages was void since they got hurt. Before everyone is completely submerged under water, Usopp and Brook untie the palace guards and Zoro tells Neptune to take his crew mates to safety.

Neptune then tells his guards to allow Hody Jones to take the palace. Neptune says that they need to regroup with Fukaboshi, so they can prepare for another battle with the New Fishman Pirates. After Zoro staggers Jones with one slash, Neptune takes Zoro, Usopp, and Brook and prepares an escape route. Neptune creates a vortex and clears a path. The ministers and the palace guards escape. However, Neptune's back gave in putting him, Zoro, Usopp, and Brook in a dangerous situation. He arrives to save them, but Jones, energized by an Energy Steroid, stops Neptune with one hand. Neptune and the three Straw Hats with him are then captured by the New Fishman Pirates.

Neptune is later seen chained once again as Hody Jones gives a speech to the Fishman Island citizens through a visual broadcast explaining about his plan to create a kingdom with himself as the ruler. Hody also announces that he is planning to execute Neptune at Gyoncorde Plaza in three hours time.

As Hody takes the king to Gyoncorde Plaza while riding on top of Sea Beasts, the Fishman Island citizens cry out to Neptune, but the king, helpless as he is, couldn't do a thing. When Hody suddenly suffers from an overdose of Energy Steroids, Neptune points out the consequences for relying on the drug too much.

He is then seen tied up at the execution site in Gyoncorde Plaza, saddened that all his soldiers there were defeated. When his sons arrive to save him, he warns them to be careful, saying all the pirates took Energy Steroids.



The princes defeat the sea beasts and fought valiantly against the officers. Unfortunately, the officers turn the tables against them by taking Energy Steroids. The princes are then defeated and chained next to the king. Fukaboshi apologizes for losing, but Neptune assures him that the New Fishman Pirates' strengths are lies. After Jinbe, Shirahoshi, and Megalo are captured and brought to the plaza, Hody assembles all of his subordinates. Hody is interrupted by Madam Shyarly, who tells Hody that Straw Hat Luffy will be the one to destroy Fishman Island and not Hody himself. After striking Shirley out of anger and bragging about his power, Hody reveals to everyone that he was the one who truly assassinated Otohime. Neptune, his sons, Jinbe, the citizens, and the lower-rank subordinates are all stunned by this revelation. When Hody explains that the human pirate was a scapegoat, Neptune is furious, but Hody responds by injuring him with a Water Shot to the chest. Hody then starts gloating about killing Otohime right in Shirahoshi's face, but the princess says that she knew all along, which deeply shocked Neptune and Jinbe. Shirahoshi explains that Megalo witnessed the truth told her about it in secret. Shirahoshi didn't reveal the truth to anyone because she was honoring her mother's last wish of holding no hatred for the killer. Hody then ridicules Shirahoshi for allowing him to go free, calling her kindness stupidity. He then tries to prove his point by torturing Neptune and the royal brothers with Yabu Same, critically injuring them. Hody is just about to take Neptune's head when Luffy (who has been hiding inside Megalo) suddenly appears and kicks Hody away. Hoe then arrives and carries away the king and princes as the rest of the Straw Hats make their unexpected appearance in the plaza.

He is later seen with his sons and Hoe when Noah is seen approaching the island. He panics, saying Noah can never be moved until "the day that must come" arrives. Neptune then explains the significance of Noah and that it must not be damaged.

He is later found by the Minister of the Left and some of the soldiers. When Neptune is asked to evacuate, he looks at the sky and says that he wishes to wait for the princes to return. After the Straw Hats defeat all the leaders of the New Fishman Pirates, everyone looks into the sky as Luffy tries to destroy Noah. Neptune apologizes to Joy Boy for not being able to keep the promise. However, the promise is saved when the Sea Kings appear and stop Noah from falling.

The Beginning of Peace
He is later shown heading towards Gyoncorde Plaza with the Minister of the Left. He is informed by the soldiers that the kidnapped mermaids are found inside the Ryugu Palace. Neptune is also informed that all the treasures in treasure room are gone. Neptune decides to ignore the treasure thieves and have his men inform the people of Fishman Island about the discovery of the kidnapped mermaids as well as dropping the charges against the Straw Hat Pirates. He then goes to the plaza where he reunites with the princes and Shirahoshi. As Jinbe offers to donate his blood to Luffy to save him, Neptune doesn't stop him and states that the law prohibiting it is just another "curse".

He then decides to let the human pirates that were enslaved by Hody go free, saying there's no reason to keep them there. He also declares that the remaining New Fishman Pirates were to live under the surveillance of his army, doing penal servitude, and that the Fishman District will be shut off. He then asks Fukaboshi of where the Straw Hats went, and is surprised when he answers that they ran away. He calls them with a Baby Den Den Mushi, and invites them to a banquet in the palace.



After enjoying banquet party, Nico Robin asks him to go outside so that they could have a talk. When Robin reveals to him that she read the Poneglyph in the Sea Forest and asks him who Joy Boy was, Neptune looks surprised, and decides to tell her because he trusts her. Neptune told Robin that Joy Boy was a man who lived during the Void Century, and that the apology message from the Poneglyph was intended to be for the Mermaid Princess of that time. He was apologizing for breaking his side of a promise he made with Fishman Island. Even though Neptune himself doesn't know of the details, he does know that one day, someone is supposed to come and carry out the promise for Joy Boy. Robin then asks Neptune if Joy Boy, who tried to use Noah, had the ability to control Sea Kings. He answers that he couldn't, and that it was the Mermaid Princess from that time who had this ability. He also says that the fact that Shirahoshi has awakened that same ability isn't a good thing. Robin tells the king of the Poneglyph she found in Skypiea two years ago, and asks if the Mermaid Princess of Joy Boy's time went by a certain name; because Shirahoshi has the same ability, and also has the same name. Neptune looks grim and surprised when he realizes that his daughter's other name is none other than Poseidon, one of the ancient weapon. Neptune is also concerned of what would happen if information about her daughter were to get out since forces around the world would desire her power.

After the treasure thief, Caribou, is discovered and sent flying out of the palace by Luffy, Nami asks Neptune why he isn't going after him. Neptune doesn't consider the treasures valuable especially after the lives of Fishman Island were saved and allows the Straw Hats to take the treasures if they can catch the thief. Neptune, his sons, Jinbe, the ministers, and some of the royal soldiers then check up on the former leaders of the New Fishman Pirates in the prison tower. They find Hody and his companions have turned into aged and frail men. Everyone then realizes that before Hody left the Neptune Army, he stole the contents of the Tamatebako. Neptune then comments on how Hody had become delusional and expresses his pity towards him.

Afterwards, Neptune has a private talk with Jinbe over the status of the Sun Pirates under Big Mom's jurisdiction. Jinbe states that they have been pretty much able to do as they please for now and admits serving under a Yonko became a great protection for his crew. Neptune notes it was because of Jinbe doing this that the island was safe after Whitebeard's death through the name of Big Mom, despite Jinbe stating that he and his crew should be doing the protection. Jinbe states that he's thinking of cutting ties with Big Mom due to Luffy's invitation to join the Straw Hat Pirates, but he worries that her anger will spill to Fishman Island. Neptune states Jinbe takes on too much responsibility and because they just gained 70,000 soldiers from the Fishman District, Neptune states he's found another flag to replace Big Mom's should they lose her protection, that being the Straw Hats', to which Jinbe happily agrees. The Minister of the Right later informs Neptune that the Tamatebako treasure box has been loaded with a bomb that will explode when somebody opens the box. This was suppossed to be a security measure after the contents of the Tamatebako were stolen ten years prior. Once they find out that Luffy gave all of the treasures to Big Mom, including the Tamatebako, Neptune and the Minister of the Right fear the possibility of Big Mom opening the box.

Afterwards, Neptune and his family and all of Fishman Island says farewell to the Straw Hat crew and Neptune tells his sons to not forget the debt they owe them.

Major Battles

 * Neptune and Ryugu Palace guards vs. Roronoa Zoro, Nami, Usopp, and Brook
 * Neptune vs. New Fishman Pirates

Trivia

 * He shares his name with Neptune, the Roman god of the sea.
 * His appearance (wild hair and beard, broad build, trident, etc.) is a common depiction of mermen in popular culture, particularly sea gods and rulers such as Triton from Disney's "The Little Mermaid".
 * The coelacanth in Indonesia (where some of them is discovered) is referred locally as "Raja Laut", meaning "King of the Sea", fitting Neptune's title as the king of Fishman Island.
 * His thick beard, bright red nose, friendliness, and "ho-ho-ho" laugh are hallmark features of Santa Claus.
 * He appears as a support character in One Piece: Gigant Battle! 2 New World. Like Shirahoshi, he can be acquired with a downloadable mission.