There are multiple crystals that will be released. Each crystal comes with a riddle that hints towards its location. There is no specific order to get the crystals, so they can be obtained in any order. However, the final riddle to reunite all the crystals will be released only when one faction has all the crystals under their control. This final riddle will hint towards the location where the reunion must take place.
If the reunion is attempted at the WRONG location, the crystals will separate and spread outwards to new locations, therefore the original riddles will be invalid. If this happens new riddles will be issued.
If you are wondering what the crystals are for, no worries, you will find out soon enough.
People you cannot ask for information:
-The Endless
-Caranore
-Aki Izayoi
-Lifeanddeath
The above 4 are the ones who know the purpose of the crystals, the locations, and the functions for this plot. They will not be allowed to lead a team trying to solve the riddles, nor will they be able to help in solving them. They can however be on the team.