>>15131356>he's gone into the mountains to find a legendary PokemonActually, the text calls it a Mythical Pokemon which is the official term for event legendaries in particular.
THERE'S A VOLCANION, DIANCIE, OR HOOPA IN THEM THAR HILLS.
Note that all of the locked power plants are in the mountain region of the Pokedex, and the Pokeball Factory which has a painting in place of the fourth plant is also in the mountain region.
I wonder if those weird statues on the gates represent Diancie or Hoopa?. We've possibly got one of the trio represented by the souvenir, so who's to say the other two aren't right under our noses elsewhere too? I also recall the Pokemon League rooms having odd looking statues with shoulders that resemble Xerneas' front...