Diancie is a mythical Pokemon accessible after defeating Fissy, the Fluoruma City Gym Leader, since you need HM8 Rock Climb. On Route 13, next to Collector Simon (wearing blue clothes) climb the stairs and go through the rock arch. Go to the end of the small cave and use Rock Climb on a slope at the end. Diancie is found at level 40.
NOTE: YOU NEED 4 DIFFERENT FORMS OF UNOWN (O, P, E, N) TO OPEN THE DOOR SAYING "OPEN" IN UNOWN ALPHABET.[[Category:]] [[Category:]][[Category:]][[Category:]]