X can use any attack, Pokepower, or Pokebody from its previous level
For example, Heroic Intervention is an instant that gives permanents you control hexproof and indestructible until the end of the turn - which is a great way to negate any effects your opponent is trying to give them.
In addition to this, Astrologians Planisphere is also an artifact, which helps Delirium costs in Legacy Delver and adds to the number of artifacts in play for Modern Affinity
When Yata-Garasu was released it was the first time this young card game had confronted a card with an effect so powerful it prevented your opponent from playing that it was almost impossible for many decks to overcome
I got into cards in general, then after a while refocused back on Greninja and made that my thing
Now the more pressing question is, how leveraged is the OP on Call of Legends cards before they decided to make this thread