Neptune is the ruler of the underwater kingdom of Neptune City. He is a muscular merman. As King of the Never Sea, he has in his possession a powerful magical trident which appears to be made of gold. It emits a glowing light and a typical sound when in use. Furthermore, he has a crown and two armbands, which also appear to be made out of gold.
His archenemy is Lord Fathom, the old mer-wizard who was once King Neptune's royal adviser who attempt to overthrow him using the power of the DarkLight Emerald, Fathom controlled the legendary giant, three-headed serpent, the Strake to attack Neptune. It wasn't until Neptune was aided by a brave pirate named, Captain Colossus he was able to seal away both Fathom and the Strake. For many years Fathom, had been seeking a way to exact his revenge upon Neptune for imprisoning him.To assure that the DarkLight Emerald wouldn't harm anyone King Neptune gave it to Queen Coralie who locked the emerald away in deep within Neptune City for years.
Roles in the series
King Neptune is briefly mentioned in the episode "Undersea Bucky!" While surfing the waves aboard Bucky Jake and his crew spot Marina in a rush with her dolphin friends informing Jake and crew underwater mermaid city of legend Neptune City has gone dark and the puny pirates offer help. Bucky revels to the crew the ability to transforming into a submarine allowing young pirates to follow Marina beneath the waves, on there way to the mermaid city Jake and his crew past by a large statue of King Neptune which is said to hold a large magical Pink Pearl that light up the city.
In the episode "Izzy's Trident Treasure", Marina and Stormy come to Pirate Island to needing the assistance of Jake and his crew. Stormy explains to them that she found a map to Neptune's Trident. It located on a mountain that is in the desert. Sense mermaids can't walk on land they can retrieve the trident. Izzy offers her assistants being an honorary mermaid, she can touch the trident.
King Neptune is briefly mentioned in the episode "Cubby's Pet Problem", Stormy's help guide Jake and his crew find the Cave of Neptune. Stormy heard legends say that an amazing sea creature lives there, but no one's ever seen it. As Jake and friends follow Stormy in there Sea Scuttlers they pass by the giant statue of King Neptune.
King Neptune's statue makes a brief appearance in the special episode "Jake's Never Land Rescue",Jake follows the magical ball of light sent by The Guardian to Mermaid Lagoon, Jake learns from Marina and Stormy, that the magical ink from the Golden Squid will restore Cubby's map. While Jake is being chased by the squid Neptune City can be spotted. After retrieving the ink and continuing his quest to save Never Land from vanishing Neptune City vanishes. Neptune City later reappears once a new Forever Tree grows and Never Land is saved.
King Neptune's statue makes a brief in the episode "Jake's Royal Rescue", while Queen Coralie is held captive by Captain Hook and his scurvy crew. Queen Coralie sings a song about her kingdom Smee, Sharky and Bones envision what it may look like.
King Neptune first appeared in the episode "The Great Never Sea Conquest". When the evil Mer-wizard named Lord Fathom is released from an underwater prison, he sets out to take over the Never Sea. Lord Fathom tricks the mermaid in revealing the location of the Dark Light Emerald the source of Lord Fathom's power. Lord Fathom releases the Strake and places it under his control and a battle erupts. King Neptune appears and tells Jake that all he needs to defeat Fathom and the Strake is to believe in himself. Using the powers of his sword, Jake finally defeats Fathom and the Strake. He then re-imprisons the Strake and destroys the DarkLight Emerald, freeing Queen Coralie, Marina, Stormy, and the sea creatures and send Fathom packing.
King Neptune is briefly mentioned in the episode special "The Legion of Pirate Villains!", Jake and his crew meet Captain Colossus who is slowly losing his strength still not recovering his strength from his first battle with the Strake. And in his weaken state couldn't recover the Treasure Keys to his treasure bestowed upon him by King Neptune that will restore his strength.
Although he doesn't appear physically, one of the magical Pirate Pieces of Eight is named after King Neptune in the episode "Stormy Seas", while Jake and his crew are sailing through a stormy Never Sea to the next pirate piece of eight located at Trident Rock. Captain Hook and Mr. Smee are on their trail for the pirate piece as well.
King Neptune statue appears in the Disney Junior online game "Jake's Never Land Rescue Game" as Jake Flo the Dolphin try to recover the Golden Squid's magical ink the King Neptune statue can be seen in the background. The King Neptune statue reappears at the end of the game once Never Land is restored.