Crown Shrine Glastrier .

Through the narrative of the story, the player battles Glastrier once, but is unable to capture it.
Instead, the player catches a Rider Calyrex (a Calyrex fused with Glastrier or Spectrier).
Glastrier can be obtained by unfusing the Ice Rider Calyrex that was caught.

Whether Calyrex is fused with Glastrier or Spectrier, depends on the choice the player made during the story.