Kappa (Japanese: 河童 or かっぱ, meaning "River child") are aquatic reptilian humanoids who inhabit the rivers and streams found all over Japan. Clumsy on land, they are at home in the water, where they thrive during the warm months. They are excellent swimmers, and despite their small size they are physically stronger than a grown man.
Kappa are generally the size and shape of a human child, with scaly skin ranging in earthy hues from deep green to bright red, even blue. Their bodies are built for swimming, with webbed, thumbless hands and feet, and a turtle-like beak and shell. Their elastic, waterproof skin reeks of fish, and is said to be removable. They possess three anuses, allowing them to pass three times as much gas as a human. Kappa forearms are attached to one another inside of their shells, and pulling on one arm will cause it to lengthen while the other one contracts. A dish-like depression lies on top of their skulls. This dish is the source of a kappa’s power and must be kept wet at all times; should the water be spilled and the dish dry up, the kappa will be unable to move and may even die.
They are amphibious creatures and have superios swimming abilities. Kappas reside in lakes and other inland water sources. They are not sea-creatures. It is possible for a Kappa to leave bodies of water, but their time outside of their pond is limited.
Adult kappa often live solitary lives, although it is common for them to befriend other yokai and even humans. Younger kappa are frequently found in family groups. Kappa are proud and stubborn, but also fiercely honorable; they never break any promises that they make. Kappa possess keen intelligence and they are one of the few yokai able to learn human languages. They are also highly knowledgeable about medicine and the art of setting bones; according to legend, these skills were first taught to humans by friendly kappa.
They will eat almost anything, but they are particularly fond of raw innards –particularly human anuses – and cucumbers. They love mischief, martial arts like sumo wrestling, and games of skill like shogi.