The Reins of Unity (Japanese: キズナのタヅナReins of Bond) is a Key Item introduced in Generation VIII. It can be used on Calyrex to fuse it with Glastrier or Spectrier into Ice Rider Calyrex or Shadow Rider Calyrex or to separate Ice Rider Calyrex or Shadow Rider Calyrex into its constituent Pokémon.
While the player has Calyrex in its Ice Rider or Shadow Rider forms, the Reins of Unity can be used to separate Calyrex from Glastrier or Spectrier. This will cause Calyrex to forget any moves that aren't available to its base form.
The Reins of Unity can only fuse together one Calyrex and Glastrier or Spectrier at a time. In order to fuse a Calyrex with a different Glastrier or Spectrier, any existing fusion must be undone.
Reins that people presented to the king. They enable those who are connected to communicate with each other. The reins separate Calyrex and its belovedsteed.
By taking the weight of either Ice Rider or Shadow RiderCalyrex and subtracting the individual weights of their components, it can be determined that the Reins of Unity weigh 1.4 kg (or 3.1 lbs).
