Kappa really exists.
Kappa often appear in various places as creatures that live in rivers and ponds. However, when we study kappas, we find out some interesting things.
Stories of the yokai, or kappa, can be found all over Japan. The shape and form of the kappa also vary considerably from region to region.
If kappas really existed, there would be many different kinds of kappas living in Japan. However, no live kappas have ever been caught or even photographed.
In other words, it is better to think of kappas as imaginary creatures from folk tales.
