Sea King
Sea King Infobox
Kanji 海王類
English Sea King Species
Romaji Kai Ō Rui
Additional Information
Notable Members N/A

Sea Kings (海王類 Kai Ō Rui, literally translated as "Sea King Species") are sea creatures which are generally much larger than normal sea creatures. They are found in great numbers along the Calm Belt around the Grand Line, although in rare occasions they can be found in other places throughout the world.


Sea Kings consist of radically different physiques and builds, so unique that no two individual Sea Kings have been recorded as being of similar build. They are serpent-like in appearance. Some may have arms and legs and one particular sea king even was noted to look like an oversized frog. Despite this, they are normally different enough to be determined from other types of sea monsters. "Lord of the Coast" is one of the smallest Sea Kings seen in the storyline, yet is still quite large in comparison to most other sea monsters. Little Garden had two large rocks that are actually the skulls of two dead Sea Kings. These skulls are far larger then the island's volcanoes.


Sea Kings will attack anything that comes within reach of them and are savage predators. In the storyline, they were seen as sea monsters who attacked without mercy and were ruthless, which led many to fear their strength and presence. Their depiction within the storyline, however, they are far more intelligent than people imagine. They also do not seem to be above lending their strength to those who need their help. Curiously enough, these Sea Kings seen were the exact same group that were first shown, when the crew unintentionally entered the Calm Belt, that were assumed to be hostile at the time.

Abilities and PowersEdit

Sea Kings make trade and travel difficult for anyone trying to cross the water where they are found as they are exceptionally fierce and strong compared to many other sea creatures. They are powerful predators and attack unprovoked with no fear or signs of backing down, the only exceptions was in the cases where they themselves were the hunted. Cases have arisen where some islands in the Grand Line close to the edge of the Calm Belt (their natural breeding ground) have ended up getting almost completely cut off from the rest of the world.

Only the strongest of ships or captains can take on a Sea King. Confrontation with one by all but a few humans is inadvisable and is considered nothing short of suicide. Many characters, see the act of killing one a sign of strength and achievement.

Their perception, however, can be easily fooled by Sea Stone. When something is covered in Sea Stone, they will not notice the object at all, as they'll mistake it for the ocean. The marines use that for their advantage and cover their ships with Sea Stone to avoid being attacked by Sea Kings.


Even though the Mermaids can communicate with fish in the sea, the Sea Kings are beyond their reach. This indicates that they are very different to the other aquatic inhabitants of the ocean. However, according to legend once every few centuries a mermaid is born with the ability to speak to the Sea Kings, on that day the world will change forever, then one day a man will appear to guide that mermaid. The name of the previous Mermaid turned out to be Poseidon, whose abilities were considered a weapon able to destroy the world and power in line with the other two ancient weapons called Pluton and Uranus. This power implies that the Sea Kings are very powerful indeed, but it is noted that due to the nature of this ability when used for the greater evil it is a most dangerous ability, as if they are drawn into a rage by the Mermaid's ability unintentionally through shock due to the mermaid's lack of control, they can destroy and sink every land mass into the ocean.