Most Pokémon are inspired by woodland animals, insects, sea creatures, and plant life, but some Pokémon are directly inspired by folkloric creatures and mythological figures like unicorns, sea dragons, phoenixes, and yokai. The Pokémon that are inspired by such rare mythological creatures also tend to be Legendary Pokémon which aren't often sighted (if ever), incredibly powerful, and surrounded by rumor and mystery.
Source：https://www.cbr.com/pokemon-based-on-mythological-creatures/
