There were two kinds of Z-Moves.
The first kind was General Z-Moves used through Type Z-Crystals.
For example, Eevee's Super Strong Limit Blast Flame Bullet and Highest Mental Destruction Wave were both General Z-Moves.
As long as a Pokémon carried the corresponding Type Z-Crystal, it had a chance to use this kind of Z-Move.
The second kind was Exclusive Z-Moves.
Exclusive Z-Moves could only be used when Pokémon of a specific species carried specific Z-Crystals and used specific base moves.
For instance, if Eevee carried an Eevee Z specially created by the Guardian Gods, it could use Extreme Evoboost, a move that summoned eight Eevee evolutions to strengthen itself—and would definitely be banned in official matches.
Exclusive Z-Moves could be said to be Z-Moves the Guardian Gods had specifically prepared for a certain species of Pokémon.
Even in the original work, there had only been a handful of Exclusive Z-Crystals.
They were even rarer than Type Z-Crystals, because they were also very difficult for the Guardian Gods to create.
Unless the circumstances were extremely special, they would neither grant Exclusive Z-Crystals nor help ordinary Pokémon develop Exclusive Z-Moves.
Besides the Exclusive Z-Moves prepared for a particular species of Pokémon, there was actually another special kind of Exclusive Z-Move.
They were Z-Moves prepared for one specific Pokémon.
Pikachu's Exclusive Z-Move, Catastropika, was a Signature Move that most Pikachu could use.
But an Exclusive Z-Move like 10,000,000 Volt Thunderbolt required Ash Pikachu Z and could only be used by Ash's Pikachu.
Rather than calling them Exclusive Z-Moves, Fang Yuan preferred to call them "Specific Z-Moves."
Without question, Z-Moves specifically prepared for a single Pokémon were far more powerful than ordinary Exclusive Z-Moves.
Fang Yuan's Magnezone had already gained considerable strength merely by mastering a kind of Blue Lightning formed by combining Electromagnetic