Kappa

Mischievous by nature, kappas delight in playing pranks on unsuspecting travelers. While usually not overtly malicious, they can be a significant nuisance, stealing clothes from unsuspecting bathers or snatching unattended food from campfires. Kappas also enjoy proving their worth in competitions of strength and, despite their propensity for trickery, are known to be honorable competitors who keep their word and remain polite in conversation.

While kappas vary in physical attributes from region to region, they're all amphibious, turtle-like humanoids with beaked mouths, webbed hands and feet, and slimy scales that range in color from bluish green to pale yellow. They often have black hair, arranged in a ring to accommodate the central depression atop their head. Water from a kappa's home lake, stream, or river fills this depression, or head bowl, which is believed to be the source of their strength. Younger kappas are easily tricked into bowing and accidentally emptying the water from their own head bowls. Losing this water makes a kappa lethargic. The longer a kappa's head bowl remains empty, the weaker they grow. While this rarely poses a serious danger for a kappa living near their home body of water, it can prove fatal to a more adventurous kappa wandering afar.

Kappas aren't inherently hostile and have been known to befriend lonely children and lend aid to stranded adventurers by providing directions or minor medical treatment. Still, many areas where kappas dwell feature posted signs warning of their presence that encourage travelers venturing near water to toss in a cucumber—kappas' favorite food—in exchange for safe passage. Kappas sometimes put up these signs themselves to increase the likelihood of receiving a tasty treat.