There is a lot of species in the Pokemon World, some truly might be rarer than others. But legends are told of Pokemon who rule or represent certain things. Pokemon that meet these requirements are called Legendary Pokemon. They are incredibly rare and often very powerful Pokemon. Some will show themselves to worthy trainers. Like the legendary Ho-oh of the Johto region who will only come out when a trainer has proven that they trust their Pokemon and together as a team are unstoppable. You also must have the rainbow wing and you may challenge this legendary Pokemon.