Blue Crystal

 is an object in. Appearing in Fort Dragonia as part of a puzzle, the Blue Crystal is guarded by the Giant Gloop and cannot be activated until the guardian is defeated in battle. Along with the Red Crystal and the others, the Blue Crystal must be deactivated in order to reach the area where Lynx and the Acacia Dragoons are preparing a ritual, using the Dragon Tear, so that their Demi-human leader can switch bodies with Serge.